Engine start roller clutch-housed type rotation transmission device

ABSTRACT

A pair of ball bearings  19, 19  and a roller clutch  20  are provided between the outer peripheral surface of the sleeve  18  fitted and fixed onto the rotating drive shaft of a starter motor and the inner peripheral surface of the pulley element  17  around which an endless belt for starting an engine extends. The roller clutch  20  has a concave section  32  on the inner peripheral surface of the clutch outer ring  30  to define a cam surface  31 . After the engine is started, the rollers  33, 33  move toward the bottom of the concave section  32  against the resilient force of the springs  40 . And, the rolling contact surface of the rollers  33, 33  is separated from the outer peripheral surface of the clutch inner ring  29 . Consequently, the friction heat which would be produced after the engine start is suppressed, and a structure having an excellent durability as a unit for starting the engine of the idling-stop vehicle is realized.

FIELD OF THE INVENTION

The rotation-transmission apparatus with built-in roller clutch forstarting an engine of this invention is mounted on the end section ofthe drive shaft of a starter motor for starting the engine of aso-called idling stop vehicle that stops the engine automaticallywithout idling when the automobile stops moving. Also, when starting theengine, it functions so as to transmit power from this drive shaft tothe crankshaft of the engine, and after the engine starts, it functionsso that the drive shaft is not rotated and driven by this engine.

BACKGROUND OF THE INVENTION

In recent years, with the purpose of saving energy and suppressing theemission of carbon dioxide, performing an idling stop by automaticallystopping the engine without idling when the automobile has stopped, hasbeen considered, and some idling-stop vehicles having this kind ofidling-stop function are actually being used. In the case of this kindof idling-stop vehicle, when the automobile stops, the vehicle-speedsensor detects a zero-speed signal, and the engine is automaticallystopped (without operating the ignition switch) based on the zero-speedsignal. On the other hand, when starting the automobile moving again,based on a signal from a clutch sensor (in the case of amanual-transmission automobile) that detects movement of the clutchpedal, or an accelerator sensor or brake sensor (in the case of anautomatic-transmission automobile) that detects when the acceleratorpedal or brake pedal moves, the automobile engine is automaticallystarted again (without operating the ignition switch). With this kind ofidling-stop automobile, it is possible to save energy and to suppressemission of carbon dioxide during this idling stop of the engine.

In the case of this kind of idling-stop automobile, it is necessary tobe able to start the engine more quickly than in the case of a normalautomobile. Therefore, it is difficult to employ the typically usedconstruction in which a pinion that is fastened to the drive shaft ofthe start motor meshes, only during starting, with a large gear that isfastened to a flywheel. Taking this into consideration, as shown in FIG.55, construction has been proposed in which an endless belt 7 runsaround a follower pulley 3 that is fastened to the end of the crankshaft2 of the engine 1, and to the drive-pulley apparatus that is fastened tothe end of the rotation-drive shaft 5 of the starter motor 4. Whenemploying this kind of construction in the starting apparatus of anengine, a drive-pulley apparatus 6 having a built-in one-way clutch isused, so that power is transmitted from the rotation-drive shaft 5 tothe endless belt 7, however, that power is not transmitted from thisendless belt 7 to the rotation-drive shaft 5. In an actual engine, thereare various auxiliary drive apparatuses installed such as an alternatorand water pump, however, since this invention is not directly related tothese drive apparatuses, they are omitted in the drawings.

With the starting apparatus for an engine having the constructiondescribed above, when starting engine, electric power flows to thestarter motor 4 to rotate and drive the drive-pulley apparatus 6, whichthen rotates and drives the crankshaft 2 by way of the endless belt 7and follower pulley 3. At this time, the one-way clutch that is builtinto the drive-pulley apparatus 6 is engaged (becomes locked), andtransmits power from the rotation-drive shaft 5 to the endless belt 7.As a result, after the engine has started, the connection with theone-way clutch is disconnected (becomes the overrun state), and therotation-drive shaft 5 of the starter motor 4 does not rotate, eventhough the endless belt 7 is running due to the rotation of thecrankshaft 2. Therefore, this starter motor 4 is not a resistanceagainst the operation of the engine 1, and the durability of thisstarter motor 4 is not damaged.

As disclosed in patent document 1 and patent document 2, using a rollerclutch as the one-way clutch in a pulley apparatus with built-in one-wayclutch that is installed in the drive-pulley apparatus 6 of this kind ofengine starting apparatus has been proposed. With construction using aroller clutch, it is possible to reduce vibration, noise and frictionthat occur when not connected better than when using a ratchetmechanism. Also, it is possible to reduce the internal friction thatoccurs when not connected better than when using a sprag-type camclutch. The following patent documents are given as the prior art of thepresent application.

Patent Document 1

Japanese Patent Publication No. Tokukai Hei 11-63170

Patent Document 2

Japanese Patent Publication No. Tokuko Hei 7-72585

Patent Document 3

Japanese Patent Publication No. Tokukai 2002-174270

Patent Document 4

Japanese Patent Publication No. Tokukai Hei 9-196090

Of the patent documents listed above, the pulley apparatus with built-inone-way clutch disclosed in patent documents 1 and 2 is intended to belocated on the end of the rotating shaft of the alternator which is anengine auxiliary apparatus, and thus the state of use differs greatlyfrom that of the starting apparatus of an engine. Therefore, even whenthis pulley apparatus with built-in one-way clutch is mounted as is onthe end of the rotation-drive shaft of a starter motor, it is notpossible to obtain sufficient durability. In other words, one reason forusing a pulley apparatus with built-in one-way clutch for the rotatingshaft of an alternator is to make the direction of the friction actingbetween the inner peripheral surface of the belt and the outerperipheral surface of the pulley constant, even though there are smallchanges in the rpm of the engine, in order to maintain the durability ofthe belt. Moreover, another reason is to increase the generatingefficiency by keeping the rotor of the alternator rotating due to itsinertia when the rpm of the engine drops.

Therefore, a pulley apparatus with built-in one-way clutch for analternator basically operates in the locked state, and the amount oftime that it operates in the overrun state is very short when comparedwith the overall time of operation. Also, the amount of continuous timein the overrun state is extremely short. Taking this into consideration,in order for a roller clutch installed in a pulley apparatus withbuilt-in one-way clutch for an alternator to securely achieve the lockedcondition when the engine is operating, well-known construction as shownin FIG. 56 and as disclosed in patent documents 1 and 2 is used.

In a first example of a roller clutch 8 using the conventionalconstruction shown in FIG. 56, an inner race 9 and outer race 10 areplaced such that they are concentric with each other, and there are aretainer 11, a plurality of rollers 12 and a plurality of springs 13, 13between the outer peripheral surface of the inner race 9 and the innerperipheral surface of the outer race 10. The outer peripheral surface ofthe inner race 9 is a cam surface having a plurality of concave sections14 called ramp sections, and the inner peripheral surface of the outerrace 10 is a simple cylindrical surface. The convex sections 15 formedaround the inner peripheral edge portion of the retainer 11 is fittedwith the aforementioned concave sections 14 to prevent the rotation ofretainer 11 relative to the inner race 9. In other words, the retainer11 and inner race 9 are such that they rotate in synchronization. Also,the springs 13 push the rollers 12 in the same circumferential directiontoward the shallow side of the concave sections 14.

In the case of this kind of roller clutch 8, when there is a tendencyfor the inner race 9 to rotate relative to the outer race 10 in theclockwise direction of FIG. 56, the rollers 12 bite into (fit into) thespace between the outer peripheral surface of the inner race 9 and theinner peripheral surface of the outer race 10, and rotation force istransmitted between the inner race 9 and the outer race 10. On the otherhand, when there is a tendency for the inner race 9 to rotate relativeto the outer race 10 in the counterclockwise direction of FIG. 56, therollers 12 are moved against the elastic force of the springs 13 to thedeep sections of the concave sections 14, and there is decrease in thesurface pressure at the points of contact between the rolling contactsurfaces of the rollers 12 and the inner peripheral surface of the outerrace 10, and the rotation force stops being transmitted between theinner race 9 and the outer race 10.

However, even when rotation force is not transmitted between the innerrace 9 and outer race 10 in this way, rubbing at the points of contactbetween the rolling contact surfaces of the rollers 12 and the innerperipheral surface of the outer race 10 is unavoidable. Therefore, whenthe overrun state continues for a long time, friction heat that cannotbe neglected occurs at the points of contact, causing the temperatureinside the roller clutch 8 to rise, and making it easy for the greaseinside this roller clutch to degrade. Furthermore, the temperature ofthe support bearing adjacent to this roller clutch 8 also rises, makingit easy for the rubber or synthetic resin seal plate in this supportbearing to degrade. In the case of a pulley apparatus with a built-inone-way clutch for an alternator, since operation is mainly in thelocked state as described above, and the amount of time of operation onthe overrun state is short, it is difficult for the rise in temperaturedue to the friction heat described above to become a problem.

On the other hand, in the case of the one-way clutch that is installedin a drive-pulley apparatus 6 for an idling-stop vehicle described aboveand as shown in FIG. 55, the amount of time that the clutch is in thelocked state is only a short time when the engine starts, and after theengine starts, the clutch is in the overrun state as long as the engineis running. Therefore, it is difficult to maintain sufficient durabilityeven when the roller clutch 8 as shown in FIG. 56 is installed in theengine starting apparatus for an idling-stop vehicle.

Taking this problem into consideration, the rotation-transmissionapparatus with built-in roller clutch for starting an engine of thisinvention is made to make it possible to sufficiently secure durability.

DISCLOSURE OF THE INVENTION

The rotation-transmission apparatus with built-in roller clutch forstarting an engine of this invention transmits power only in a specifieddirection between a rotating member that rotates together with theengine crankshaft during use and the rotating shaft of a motor forstarting an engine that is inserted through the center of this rotatingmember and that rotates only in the specified direction during use; andcomprises a pair of support bearings that are located such that they arespaced apart in the axial direction in a circular-ring shaped spacebetween the inner peripheral surface of the rotating member and theouter peripheral surface of the rotating shaft; and a roller clutch thatis located between the pair of support bearings in this circular-ringshaped space.

Also, this roller clutch becomes engaged when the rotating shaft rotatesin the specified direction and transmits power from this rotating shaftto the rotating member, however, when the rotating member rotates in thespecified direction faster than the rotating shaft, the roller clutchruns idle and does not transmit power from the rotating member to therotating shaft.

Moreover, the pulley with built-in roller clutch for a starter motordescribed in claim 1 comprises: a first support bearing that is locatedon the one side in the axial direction of the pulley; a second supportbearing that is located on the other side in the axial direction of thepulley, and a roller clutch portion that is located between the firstsupport bearing and second support bearing; and this roller clutchportion becomes locked in one direction of rotation, and becomesunlocked in the other direction, and a cam surface is formed on theinner peripheral surface of the pulley or on the inner peripheralsurface of the clutch outer ring that is fastened inside the pulley.

Also, in the rotation-transmission apparatus with built-in roller clutchfor starting an engine described in claim 2, when the plurality ofrollers of the roller clutch are located in the deepest section ofconcave sections that define the cam surface for allowing these rollersto move in the radial direction of the rotating member, the size of thespace that exists between the rolling contact surfaces of the rollersand the outer peripheral surface of the rotating shaft or the outerperipheral surface of the clutch inner ring that is fitted onto andfixed to this rotating shaft becomes larger than the radial space of thesupport bearings.

Furthermore, in the rotation-transmission apparatus with built-in rollerclutch for starting an engine described in claim 3, the support bearingsand the roller clutch are lubricated using the same kind of grease,which has a synthetic base oil and a urea type bodying agent.

In the rotation-transmission apparatus with built-in roller clutch forstarting an engine described in claim 4, the support bearings are ballbearings, and the retainer that holds the plurality of balls such thatthey roll freely is a crown-type retainer made of synthetic resin, and apartial cylindrical surface having a center axis that is parallel withthe center axis of the retainer is formed on the inside surface of thepockets of this retainer on the parts on both sides in thecircumferential direction that face the rolling contact surface of theballs.

In the rotation-transmission apparatus with built-in roller clutch forstarting an engine described in claim 5, the seal rings are located onboth ends of the support bearings, and of these seal rings, the sealring located on the outside, or the side opposite to the roller clutch,is a contact type seal ring, and the seal ring on the inside, or theside of the roller clutch, is of the non-contact type.

Also, in the rotation-transmission apparatus with built-in roller clutchfor starting an engine described in claim 6, the cam surface forallowing the plurality of rollers of the roller clutch move in theradial direction of the rotating member is formed on the innerperipheral surface of the rotating member or on the inner peripheralsurface of the clutch outer ring that is fitted into and fastened insidethis rotating member, and the outer peripheral surface of the rotatingshaft or the outer peripheral surface of the clutch inner ring that isfitted onto and fixed to the rotating shaft is a cylindrical surface.Also, a chemically processed layer is formed on at least one of theouter peripheral surface of this cylindrical surface and the surface ofthe rollers.

Moreover, the rotation-transmission apparatus with built-in rollerclutch for starting an engine described in claim 7 comprises a pluralityof protruding supports that are located on the outer peripheral surfacein the middle section in the axial direction of the retainer for holdingthe plurality of rollers of the roller clutch, in locations that facethe side surface of the base sections of the plurality of springs thatpress these rollers, and such that they protrude in the radialdirection, and eave sections that are located on the side surfaces ofthese protruding supports that face the side surface of the base sectionof the elastic members, in the section further separated toward theouter-diameter side from the side surface of the base sections, and thatprotrude toward the base section side of these elastic members. Also,the length by which these eave sections protrude from the side surfaceof the protruding supports is greater than the thickness of the portionof the base section of the springs that face this side surface.

Also, in the rotation-transmission apparatus with built-in roller clutchfor starting an engine described in claim 8, the cam surface forallowing the plurality of rollers of the roller clutch to move in theradial direction of the rotating member is formed around the innerperipheral surface of the rotating member or the inner peripheralsurface of the clutch outer ring that is fitted into and fastened tothis rotating member, and the outer peripheral surface of the rotatingshaft or the outer peripheral surface of the clutch inner ring that isfitted onto and fastened to this rotating shaft is a cylindricalsurface. Also, the plurality of rollers are held between the innerperipheral surface of the cam surface and the outer peripheral surfaceof the cylindrical surface, and the springs come in contact with therolling contact surfaces of the rollers at a location further on theinside in the radial direction of the retainer of the roller clutch thanthe location of the front end of the rolling contact surfaces of theserollers, in the direction of movement of the center axis of therespective rollers in the state where these rollers roll along theplurality of concave sections of this cam surface to the deep side ofthe concave sections.

In the rotation-transmission apparatus with built-in roller clutch forstarting an engine described in claim 9, the roller clutch comprises: aplurality of rollers that are located between the inner peripheralsurface of the rotating member and the outer peripheral surface of therotating shaft; springs for pressing the rollers in the samecircumferential direction of the rotating member and rotating shaft; anda retainer for holding these rollers. Also, these springs comprise amain section that comes in contact with part of the retainer, and a pairof pressure sections whose base ends are connected to and continuouswith both ends of the main section. Also, when these pressure sectionsare in contact with the rolling contact surfaces of the rollers, theyexpand and compress independently. Moreover, the location of the centerof gravity of the rollers in the axial direction is located between theareas of contact in these pressure sections with the rolling contactsurfaces of the rollers, and when the pressure sections are compressedby the rollers, the space in the axial direction between the areas ofcontact in these pressure sections with the rolling contact surfaces ofthe rollers is half or more the length in the axial direction of therollers.

In the rotation-transmission apparatus with built-in roller clutch forstarting an engine described in claim 10, the roller clutch comprises aplurality of rollers that are located between the inner peripheralsurface of the rotating member and the outer peripheral surface of therotating shaft; springs for pressing these rollers in the samecircumferential direction of the rotating member and rotating shaft; anda retainer that holds these rollers. Moreover, these springs comprise amain section that comes in contact with part of the retainer, and a pairof pressure sections whose base ends connect to and are continuous withboth ends of the main section, and of these, in the state where thepressure sections come in contact with the rolling contact surfaces ofthe rollers, they extend or compress independently, and these pressuresections are curved such that the radius of curvature is graduallydecreased going from the base end toward the tip end.

In the rotation-transmission apparatus with built-in roller clutch forstarting an engine described in claim 11, the retainer for holding theplurality of rollers of the roller clutch comprises a pair of rimsections that are spaced apart in the axial direction of thecircular-ring shaped space and located parallel with each other, and aplurality of column sections that are spaced apart in thecircumferential direction of the circular-ring shaped space and locatedparallel with each other to connect the rim sections, and grease pocketsfor holding grease are formed on the inner peripheral surfaces of thesecolumn sections.

With the rotation-transmission apparatus with built-in roller clutch forstarting an engine of this invention constructed as described above itis possible to improve durability.

In other words, in the case of the pulley with built-in roller clutchfor starter motor described in claim 1, the rolling contact surfaces ofthe plurality of rollers of this roller clutch are guided by the innerperipheral surface of the pulley or by the inner peripheral surface ofthe clutch outer ring that is fitted into and fastened to the pulley.Therefore, it is possible to keep friction heat that is generated insidethe roller clutch when rotating to a minimum, and thus it is possible toimprove the durability of the roller clutch and the adjacent supportbearings, and improve the durability of the pulley with built-in rollerclutch for a starter motor.

Also, in the case of the rotation-transmission apparatus with built-inroller clutch for starting an engine described in claim 2, it ispossible for the rolling contact surfaces of all of the rollers and theouter peripheral surface of the rotating shaft or the outer peripheralsurface of the clutch inner ring that is fastened around the outside ofthis rotating shaft to become securely separated after the enginestarts, even when the center axis of the rotating member and the centeraxis of the rotating shaft are eccentric due to radial clearance of thesupport bearings (by just the amount of this radial clearance).Therefore, it is possible to improve the durability of therotation-transmission apparatus with built-in roller clutch for startingan engine.

Moreover, in the case of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine described in claim 3, itis possible to secure excellent shear stability and heat resistance(high-temperature stability) of the grease filled in the roller clutch,as well as it is possible to prevent the occurrence of problems such asdegradation of grease, due to mixing of the grease, that is filled inthe roller clutch and in the support bearings, and thus it is possibleto improve the durability of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine.

Furthermore, in the case of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine described in claim 4, itis possible to increase the span of the applied radial load and increasethe rigidity, as well as improve the durability. Also, since theretainer is crown shaped and made of synthetic resin, it is difficultfor the abrasion powder produced in the retainer to cause the grease todegrade. Moreover, since the hardness of the abrasion powder is low,this abrasion powder does not cause damage such as indentation of theouter race track or inner race track to occur, and thus the pealing lifeof these race tracks is not worsened. Therefore, it is possible toimprove the durability of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine.

Also, in the case of the rotation-transmission apparatus with built-inroller clutch for starting an engine described in claim 5, it ispossible to prevent foreign matter such as dust or dirt in the air fromgetting into the space inside the support bearings and roller clutch, aswell as it is possible to prevent grease that is filled inside theseinternal spaces from leaking out, thus it is possible to improve thedurability of the rotation-transmission apparatus with built-in rollerclutch for starting an engine. It is also possible to decrease therotation resistance when the roller clutch is in the overrun state.

In the case of the rotation-transmission apparatus with built-in rollerclutch for starting an engine described in claim 6, a chemicalconversion layer such as manganese phosphate is formed on the surfacesof the plurality of rollers of the roller clutch or the outer peripheralsurface of the cylindrical surface or both of them. The surface of thislayer processed through chemical conversion is rough. Therefore, it ispossible to increase the static friction coefficient at the points ofcontact between the surfaces of the plurality of rollers and thecylindrical surface. Therefore, in the locked state of the rollerclutch, it is difficult for slipping to occur at the points of contactbetween the surfaces of the rollers and the cylindrical surface, andthus it is easier to achieve the locked state. On the other hand, whenthe roller clutch is in the overrun state, the chemical conversion layermakes it possible to prevent metallic contact between the surfaces ofthe plurality of rollers and the cylindrical surface. Together withthis, lubricant is held between the crystal grains of this chemicalconversion layer, and this held lubricant makes it is possible toimprove the state of lubrication at the areas of sliding contact betweenthe surfaces of the rollers and the cylindrical surface. Therefore, whenthe roller clutch is in the overrun state, it is difficult for wear andseizure to occur at these points of sliding contact, and thus it ispossible to improve the durability of the rotation-transmissionapparatus with built-in roller clutch for starting an engine.

Also, in the case of the rotation-transmission apparatus with built-inroller clutch for starting an engine described in claim 7, it ispossible to prevent the springs from coming out of place or shiftingoutward with respect to the protruding supports even when largecentrifugal force acts on the springs due to high-speed rotation of theretainer. Therefore, it is possible to improve the reliability anddurability of the roller clutch. As a result, it is possible to preventthis outward shifting and to improve the reliability and durability ofthe rotation-transmission apparatus with built-in roller clutch forstarting an engine regardless of there being a tendency for the springto easily shift toward the outer-diameter side of the retainer due tothe fact that the retainer continues to rotate together with therotating member at high speed for a long time after the engine starts.

Moreover, in the case of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine described in claim 8, whenchanging from the locked stat to the overrun state, it becomes easierfor the rollers to roll along the concave sections of the cam surface tothe deep side of the concave sections due to the action of thecentrifugal force. Therefore, in the overrun state, it is possible toprevent a state of sliding contact from being kept between the rollingcontact surfaces of the rollers and the outer peripheral surface of thecylindrical surface, and to suppress the occurrence of friction heat andfriction loss. Therefore, it is possible to improve the durability andperformance of the roller clutch. As a result, regardless of whethersprings having a large elastic force are used for pressing the rollers,it is possible to improve the durability and performance of therotation-transmission apparatus with built-in roller clutch for startingan engine.

Furthermore, in the case of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine described in claim 9, itis possible to prevent the attitude of the rollers from shifting in adirection that the center axis would tilt from the proper position(becoming skewed) when the springs are pressed by the rollers in theoverrun state. Therefore, it is possible to prevent uneven wear andabnormal heat due to this kind of skewing of the rollers, and thus it ispossible to improve the durability (long life) of therotation-transmission apparatus with built-in roller clutch for startingan engine.

In other words, in the case of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine described in claim 9, thesprings pressing the rollers to come in contact with the rollers,through a pair of pressure sections in the springs, at two pointsseparated in the axial direction. Therefore, even when the location ofthe points of contact between the pressure sections and the rollerschanges a little, it is possible to prevent large changes in the forceand moment applied to the rollers, and thus it is possible to keep theattitude of the rollers in the proper location.

Also, since the springs come in contact with the rollers at two pointsby way of the pair of pressure sections, it is possible for thesepressure sections to extend and compress independently. Therefore, whenthe rollers become skewed, a large reaction force occurs in the pressuresection on the side where there is a large amount of displacement(amount of extension or compression). As a result, a moment is appliedto the rollers, so that the original attitude of the rollers isrestored, and therefore the attitude of the rollers are kept proper.Also, the location of the center of gravity of the rollers in the axialdirection is located between the areas of contact in the pressuresections with the rolling contact surfaces of the rollers, so it ispossible to prevent the location of the center of gravity of the rollersand the direction of pressure by the pressure sections from becomeimproper. As a result, it is possible to prevent moments from beingapplied to the rollers, and thus to prevent skewing of the rollers.

Moreover, when the pressure sections are pressed by the rollers, thespace in the axial direction between the areas of contact in thepressure sections with the rolling contact surfaces of the rollers ishalf or more the length in the axial direction of the rollers.Therefore, no matter how the attitude of the rollers changes, or nomatter how the pressure sections are pressed by the rollers, it ispossible to always keep the center of gravity of the rollers locatedbetween the areas of contact. Therefore, it is possible to sufficientlysecure an attitude stabilizing action by having the rollers come incontact with the springs at two points that are separated in the axialdirection, and thus it is possible to keep the attitude of rollers in aproper position.

Also, in the case of the rotation-transmission apparatus with built-inroller clutch for starting an engine described in claim 10, togetherwith being able to sufficiently reduce the stress applied to the baseends of the pressure sections, it is possible to secure the necessarypressure for without increasing the size of the springs. In other words,the stress applied to these pressure sections becomes larger the closerto the base ends, and becomes larger the smaller the radius of curvatureis (curvature becomes large). However, in the case of therotation-transmission apparatus with built-in roller clutch for startingan engine described in claim 10, it is possible to reduce the stressapplied at these base ends by making the radius of curvature at the baseend of the pressure sections large (small amount of curvature). Also,together with this, it is possible to maintain pressure of the pressuresections without increasing the size of the springs by making the radiusof curvature at the base ends of these pressure sections (large amountof curvature). Therefore, it is possible to prevent uneven wear andabnormal heat generation due to skewing of the rollers, and it ispossible to improve the durability of the rotation-transmissionapparatus with built-in roller clutch for starting an engine.

Also, in the case of the rotation-transmission apparatus with built-inroller clutch for starting an engine described in claim 11, it ispossible to supply grease, from the grease reservoir, to the areas ofcontact between the rolling contact surfaces of the rollers and theouter peripheral surface of the rotating shaft or the outer peripheralsurface of the clutch inner ring that is fitted and fastened onto thisrotating shaft. Therefore, even when there is rubbing between both ofthese surfaces, it is possible to suppress wear between these surfacesand to improve the durability of the rotation-transmission apparatuswith built-in roller clutch for starting an engine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view to show a whole construction of a firstexample of embodiment of the present invention.

FIG. 2 is a cross sectional view taken along the line A-A in FIG. 1 toshow the roller clutch only.

FIG. 3 is an enlarged view of Portion B in FIG. 2.

FIG. 4 is a schematic view to show a portion of the roller clutch, takenin the same direction to that of FIG. 3, to explain the size of theclearance with respect to the roller clutch.

FIG. 5 is an enlarged view of part of the retainer of the supportbearing in one example.

FIG. 6 is a schematic view to explain the size of the wedge angle whichis desirable in achieving the locked state.

FIG. 7 is a schematic view to explain the size of the wedge angle whichis desirable in separating the rolling contact surface of the roller andthe outer peripheral surface of the clutch inner race.

FIG. 8 is a cross sectional view to show the whole construction of thesecond example of embodiment of the present invention.

FIG. 9 is a cross sectional view to show the whole construction of thethird example of embodiment of the present invention.

FIG. 10 is a cross sectional view to show the whole construction of thefourth example of embodiment of the present invention.

FIG. 11 is a cross sectional view to show the whole construction of thefifth example of embodiment of the present invention.

FIG. 12 is a cross sectional view to show the whole construction of thesixth example of embodiment of the present invention.

FIG. 13 is a cross sectional view to show the whole construction of theseventh example of embodiment of the present invention.

FIG. 14 is a cross sectional view to show the whole construction of theeighth example of embodiment of the present invention.

FIG. 15 is a cross sectional view to show the whole construction of theninth example of embodiment of the present invention.

FIG. 16 is a cross sectional view to show the whole construction of thetenth example of embodiment of the present invention.

FIG. 17 is a cross sectional view to show the whole construction of theeleventh example of embodiment of the present invention.

FIG. 18 is a cross sectional view to show the whole construction of thetwelfth example of embodiment of the present invention.

FIG. 19 is a view similar to FIG. 22 to show a reference example for thepresent invention.

FIG. 20 is a view similar to FIG. 23 to show the thirteenth example ofembodiment of the present invention.

FIG. 21 is a cross sectional view to show a first example of theconventional structure of the pulley apparatus with built-in rollerclutch.

FIG. 22 is a cross sectional view taken along the line C-C in FIG. 21with part of it omitted.

FIG. 23 is a view similar to FIG. 22 to show a second example of theconventional structure of the pulley apparatus with built-in rollerclutch.

FIG. 24 is a view similar to FIG. 23 to explain forces applied to therollers from the cylindrical surface and the cam surface.

FIG. 25 is a cross sectional view to show a fourteenth example ofembodiment of the present invention.

FIG. 26 is a partly cut-away, perspective view of the retainer andsprings taken from FIG. 25.

FIG. 27 is a cross sectional view taken along the line D-D in FIG. 26.

FIG. 28 is a cross sectional view, corresponding to the cross section ofE-E of FIG. 25, to show a fifteenth example of embodiment of the presentinvention to explain the positional relation between the clutch innerrace and the rollers in the state before the clutch inner race ispressed on the inner diameter side of the rollers.

FIG. 29 is a cross sectional view to show an engagement state of thebeveled section formed in the clutch inner raced and the rollers at theouter peripheral edge portion of their ends.

FIG. 30 is a partly omitted, cross sectional view to show a sixteenthexample of embodiment of the present invention.

FIG. 31 is a cross sectional view, similar to FIG. 8, to show aseventeenth example of embodiment of the present invention in the statewhen the locked state is transited to the over-run state.

FIG. 32 is a perspective view to show part of a second example of theconventional structure of the roller clutch with the inner and outerraces omitted.

FIG. 33 is a cross sectional view to show part of a third example of theconventional structure of the roller clutch with the inner and outerraces omitted.

FIG. 34 is a view, corresponding to the cross section of F-F in FIG. 25,to show the roller clutch in an eighteenth example of embodiment of thepresent invention.

FIG. 35 is an enlarged view of Portion G.

FIG. 36 is a view of the rollers and springs in the examples, wherein(a) shows a free state and (b) shows a compressed state.

FIG. 37 is a cross sectional view, similar to FIG. 36( a), to show anineteenth example of embodiment of the present invention.

FIG. 38 is a cross sectional view, similar to FIG. 36( a), to show atwentieth example of embodiment of the present invention.

FIG. 39 is a cross sectional view, similar to FIG. 36( a), to show atwenty-first example of embodiment of the present invention.

FIG. 40 is a cross sectional view, similar to FIG. 36( a), to show atwenty-second example of embodiment of the present invention.

FIG. 41 is a cross sectional view, similar to FIG. 36( a), to show afirst example of the conventional spring.

FIG. 42 is a cross sectional view, similar to FIG. 36( a), to show asecond example of the conventional spring.

FIG. 43 is a cross sectional view, similar to FIG. 36( a), to show athird example of the conventional spring.

FIG. 44 is a partly cut-away, perspective view of the retainer to beinstalled in the roller clutch in a twenty-third example of embodimentof the present invention.

FIG. 45 is a view in the direction of Arrow H in FIG. 44.

FIG. 46 is a cross sectional view, similar to FIG. 44, to show atwenty-third example of embodiment of the present invention.

FIG. 47 is a cross sectional view, similar to FIG. 44, to show atwenty-fourth example of embodiment of the present invention.

FIG. 48 is a cross sectional view, similar to FIG. 44, to show atwenty-fifth example of embodiment of the present invention.

FIG. 49 is a cross sectional view to show the whole construction of thepulley apparatus with built-in roller clutch according to a priorinvention.

FIG. 50 is a cross sectional view taken along the line I-I of FIG. 49 toshow the roller clutch.

FIG. 51 is an enlarged view of Portion J in FIG. 50.

FIG. 52 is a perspective view to show part of the clutch retainer in aconventional structure taken from the outer diameter side.

FIG. 53 is a perspective view to show part of the clutch retainer in aconventional structure taken from the inner diameter side.

FIG. 54 a view similar to FIG. 52 to show a clutch retainer with springsinstalled in it.

FIG. 55 is a schematic view of an apparatus for starting an engine foran idling-stop vehicle.

FIG. 56 is a partial cross sectional view to show a first example of thetypical roller clutch in a conventional structure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 5 show a first example of embodiment of the invention. Thepulley apparatus with built-in roller clutch 16, which is arotation-transmission apparatus with built-in roller clutch for startingan engine according to the present example, is an engine-startingapparatus for an idling-stop vehicle as shown in FIG. 55 describedabove, and it is used as the drive-pulley apparatus 6 for transmittingthe rotation of the rotation-drive shaft 5 of the starter motor 4 to theendless belt 7. Also, it is constructed such that when electric powerflows to the starter motor 4, the rotation of the rotation-drive shaft 5is transmitted to the endless belt 7, and that when this endless belt 7is driven by the engine 1 after the start of the engine 1, power is nottransmitted to the rotation-drive shaft 5 from the endless belt 7.

In this kind of pulley apparatus with built-in roller clutch 16, apulley element 17, which is a rotating member around which the endlessbelt 7 is placed around its outer peripheral surface, and a sleeve 18,which is fitted and fastened onto the tip end of the rotation-driveshaft 5, are placed such that they are concentric with each other. Also,a pair of deep-groove ball bearings 19, which function as supportbearings, and a roller clutch 20 are located between the outerperipheral surface of this sleeve 18 and the inner peripheral surface ofthe pulley element 17. In order to install these ball bearings 19 androller clutch 20, the inner peripheral surface of the pulley element 17is a simple cylindrical surface, and the outer peripheral surface of thesleeve 18 is a stepped cylindrical surface having a large-diametersection 21 in the middle in the axial direction and small-diametersections 22 on both ends which are continued to the large-diametersection 21 through a stepped portion.

Moreover, the roller clutch 20 is located in the middle section in theaxial direction of the ring-shaped space that exists between the outerperipheral surface of the sleeve 18 and the inner peripheral surface ofthe pulley element 17, and the ball bearings 19 are located near bothends in the axial direction of this ring-shaped space such that they arelocated on both sides in the axial direction of the roller clutch 20. Ofthese, the ball bearings 19 function such that the pulley element 17 andthe sleeve 18 are concentric with each other, and that both of thesemembers 17, 18 are allowed to freely rotate relative to each other. Inthis example, by placing these ball bearings 19 on the opposite sides ofthe roller clutch 20, it is possible to lengthen the span to which theradial loads are applied, thus making it possible to increase therigidity and maintain durability. Also, by giving angle of contact tothese ball bearings 19 in opposite directions from each other(preferably a back-to-back combination type), they freely support axialloads in both directions that are applied to the pulley element 17.

Each of the ball bearings 19 comprises an outer race 24 having an outerrace track 23 in the deep-groove type formed around its inner peripheralsurface, an inner race 26 having an inner race track 25 in thedeep-groove type formed around its outer peripheral surface, and aplurality of balls 27 rollably located between the outer race trace 23and inner race track 25. Also, the outer race 24 is fixed throughinterference fit to the inner peripheral surface on both ends of thepulley element 17, and the inner race 26 is fixed through interferencefit to the small-diameter sections 22 formed around the outer peripheralsurface on both ends of the sleeve 18. Moreover, in this state of eachball bearing 19, one of the end surfaces in the axial direction of theinner race 26 comes in contact with the stepped surface connecting thelarge diameter-section 21 and the small-diameter sections 22.

Also, in each ball bearing 19, the openings on both ends of the spacewhere the balls 27 are located are blocked by seal rings 28 a, 28 bprovided between the inner peripheral surfaces on both ends of the outerrace 24 and the outer peripheral surfaces on both ends of the innerraces 26. Lubricant such as grease is filled in the space to lubricatethe points of rolling contact between the rolling contact surfaces ofthe balls 27 and the outer-race 23 and inner-race 25. The type of greaseused in this case is not particularly limited, however, it is preferredthat a grease having synthetic oil as the base oil, and a urethane typebodying or thickening agent, be used because of its excellent heatresistance (high-temperature stability).

Also, the construction of the seal rings 28 a, 28 b is not particularlylimited. A general type seal ring comprising a circular-ring shaped coremade of metal plate and an elastic material such as an elastomer likerubber reinforced with the metal core can be used. However, it ispreferred that the seal rings 28 a on the outside (side opposite fromthe roller clutch 20) of the ball bearings 19 be a so-called contacttype seal ring whose inner peripheral edge comes in sliding contact allaround the outer peripheral surface of the inner race 26. The reason forthis is to prevent foreign matter, such as dirt or dust, flying from theoutside from getting inside the bearing, as well as to prevent thegrease inside the space from leaking out.

On the other hand, the seal rings 28 b on the inside (side toward theroller clutch 20) can be a contact type, however, it is also possible touse so-called non-contact type of seal ring whose inner peripheral edgecomes close to and faces the outer peripheral surface of the inner race26 through a labyrinth space. By using a non-contact type of seal ring,it is possible to reduce the rotation resistance during overrun of theroller clutch 20 by that amount. Furthermore, as will be describedlater, when the roller clutch 20 and the ball bearings 19 are lubricatedusing the same type of grease, it is possible to even omit the sealrings 28 b on the inside. In either case, it is preferred thatfluororubber having excellent heat resistance be used as the elasticmaterial of the seal rings 28 a, 28 b, in order to obtain excellentdurability regardless of friction heat that occurs when the outer race24 rotates at high speed while the inner race 26 is stopped.

It is also possible to form a minute hole enough for air to pass throughin the outside seal ring 28 a mounted in at least one of the ballbearings 19 (when the inside rings 28 b are contact type, a hole can beformed in the inside seal ring 28 b as well). When the ball bearings 19are fitted between the inner peripheral surface of the pulley element 17and the outer peripheral surface of the sleeve 18, these holes allow airin the space between the peripheral surfaces to be output, and have thefunction of suppressing an increase in pressure inside this space. Bysuppressing an increase in pressure in this space in this way, it ispossible to prevent deformation such as burrs from occurring on the sealrings 28 a, 28 b installed in the ball bearings 19, and thus to preventthe seal formed by these seal rings 28 a, 28 b from becoming bad.Moreover, it is possible to prevent deformation even when the pressureinside the aforementioned space changes due to temperature change thatoccurs during operation and when stopped, and thus it is possible toprevent the seal from becoming bad.

The construction and material of the retainer 41 that holds the balls 28inside the ball bearings 19 such that they rotate freely are notparticularly limited. It can be a pressed retainer in a wave-shape madeof metal as shown in FIG. 1. However, in order to obtain even betterdurability, it is also possible to use a crown-shaped retainer made ofsynthetic resin as the retainer 41. In the case of using a syntheticresin retainer, the retainer is lighter than a metal retainer, so theresponse to changes in angular velocity is better. Also, when powderfrom abrasion of the retainer occurs, it is more difficult for theabrasion powder to cause the grease to become bad. Moreover, since thehardness of the abrasion powder is low, it does not cause damage such asindentation to the outer race tracks 23 or inner race tracks 25, and soit does not lower the flaking life of these tracks 23, 25. It ispreferred that polyamide 46 having excellent heat resistance be used asthe synthetic resin for this crown-shaped retainer. Also, in order toimprove the strength for suppressing deformation during high-speedrotation, it is also possible for the synthetic resin to contain areinforcing material such as glass fiber.

Furthermore, as shown in FIG. 5, when using a crown-shaped retainer, itis possible, on the inside of the pocket 42 for holding the balls 27, toform the sections on both ends in the circumferential direction thatface the rolling contact surface of the balls 27 (so-called equatorsection where the balls 27 come in actual rolling contact with the outerrace track 23 and inner race track 25) such that they have a partialcylindrical surface 43 whose center axis α is parallel with the centeraxis of the retainer 41 a. By using a retainer 41 a having pockets 42with this kind of shape, it is possible to put a sufficient amount ofgrease between the inner peripheral surfaces of these pockets 42 and therolling contact surfaces of the balls 27 to improve the lubrication ofthe ball bearings 19. Furthermore, it is possible to reduce theresistance that acts between the inner peripheral surfaces of thepockets 42 and the rolling contact surfaces of the balls 27, and reducethe rotation resistance of the ball bearings 19, and thus it is possibleto reduce the rotation resistance during overrun of the roller clutch20. Reducing this rotation resistance reduces the load on the engine 1and contributes to the improvement of running performance such asacceleration performance and fuel-consumption performance.

Moreover, in the roller clutch 20, only when the pulley element 17 has atendency to rotate in a specified direction relative to the sleeve 18,rotation force is freely transmitted between the pulley element 17 andthe sleeve 18. In order to use this kind of roller clutch 20, the clutchinner ring 29 is tightly fitted onto the large-diameter section 21 ofthe sleeve 18. This clutch inner ring 29 is formed into a generallycylindrical shape by plastic working such as pressing of steel plate,such as carburized steel plate, and the inner and outer peripheralsurfaces are both simple cylindrical surfaces. In other words, theclutch inner ring 29 is formed by performing heat treatment such ascarburization or carbonitriding after performing plastic working such aspressing of steel plate such as carburized steel plate, or by performingheat treatment by normal quenching and tempering or nitriding of bearingsteel.

On the other hand, the inner peripheral surface of the clutch outer ring30 which is tightly fitted onto the middle section of the innerperipheral surface of the pulley element 17, and it functions as a camsurface 31. In other words, by forming a plurality of concave sections32 called ramp sections around the inner peripheral surface of theclutch outer ring 30 such that they are spaced uniformly in thecircumferential direction as shown in FIG. 2 and FIG. 3, the innerperipheral surface functions as a cam surface 31. This kind of clutchouter ring 30 is also formed into a generally cylindrical shape byplastic working such as pressing of steel plate like carburized steel.That is, the clutch outer ring 30 is made by performing heat treatmentsuch as carburization or carbonitriding after pressing of the steelplate like carburized steel.

Moreover, the plurality of rollers 33 that make up the clutch roller 20together with the clutch inner ring 29 and clutch outer ring 30 aresupported, such that they can rotate freely and move a little in thecircumferential direction, by a clutch retainer 34 that is fitted ontothe clutch outer ring 30 such that it cannot rotate with respect to theclutch outer ring 30. For these rollers 33, it is possible to usebearing steel that has been heat treated by normal quenching andtempering or by nitriding, ceramic, or chromium steel that has been heattreated by nitriding. Moreover, the clutch retainer 34 is formed into agenerally cage-type cylindrical shape from a synthetic resin (forexample, a synthetic resin like polyamide 66, polyamide 46 orpolyphenylene sulfide that is mixed with about 20% glass fiber), andcomprises a pair of circular ring shaped rim sections 35, and aplurality of a column sections 36 that connect these rim sections 35together.

Also, the sections surrounded on four sides by the inside surfaces ofthe rim sections 35 and the side surfaces in the circumferentialdirection of the columns sections 36, define pockets 37 for holding therollers 33 such that they can rotate freely as well as move freely alittle in the circumferential direction. Moreover, as shown in FIG. 3,convex section 38 are formed at a plurality of locations around theouter peripheral surface of the rim sections 35 such that they arefitted with the concave section 32 formed on the inner peripheralsurface of the clutch outer ring 30, such that the clutch retainer 34 ismounted to the clutch outer ring 30 such that it cannot rotate relativeto the clutch outer ring 30. Also, by holding the clutch retainer 34 onboth sides in the axial direction by inward facing collar sections 39 a,39 b that are formed on both end sections in the axial direction of theclutch outer ring 30, this clutch retainer 34 is not able to move in theaxial direction with respect to the clutch outer ring 30.

Furthermore, springs 40 are mounted as shown in FIGS. 2 and 3 on one ofthe side surfaces in the circumferential direction of the columnsections 36 of the clutch retainer 34. These springs 40 that are locatedon each column section elastically press the rollers 33 that held in thepockets 37 in the same direction (to the left or counterclockwisedirection in FIGS. 2 and 3) in the circumferential direction of theclutch retainer 34 toward the section in cylindrical space formedbetween the cam surface 31 and outer peripheral surface (cylindricalsurface) of the clutch inner ring 29 where the width in the radialdirection becomes narrow. In the example shown in the figures, thesprings 40 are compression coil springs, however, actually plate springsthat are made by bending spring steel into a triangular-shaped hook areoften used for these springs 40. It is also possible to use syntheticresin springs that are made in one piece with the clutch retainer 34.

Moreover, in this example, the cross-sectional shape of the concavesections 32 that are formed on the inner peripheral surface of theclutch outer ring 30 is not straight line but a simple arc shape. Thecenter of curvature of the arc of this cross-sectional shape is locatedaway from the center of the clutch outer ring 30. Also, the radius ofcurvature of the arc and the center point are set such that this arc isa curve resembling a logarithmic spiral, and the so-called wedge angleis constant. This wedge angle is the angle between the tangent line atthe point of contact between the concave sections 32 and the rollingcontact surface of the rollers 33, and the tangent line at the point ofcontact between the outer peripheral surface of the clutch inner ring 29and the rolling contact surface of the rollers 33. In this example, bysuitably regulating the radius of curvature and center point of the arc,the wedge angle is nearly constant even when the rollers 33 are wedgedinto any section between the concave sections 32 and the outerperipheral surface of the clutch inner ring 29.

It is preferred that the size of the wedge angle be in the range from 8degrees to 11 degrees. The reason for this is explained using FIG. 6.When the roller clutch 20 is transmitting torque between the pulleyelement 17 and sleeve 18, the load applied to the rollers 33 is assumedto be the same, and with respect to the load P applied to the roller 33from the outer peripheral surface of the clutch inner ring 29, thesmaller the wedge angle α is, the component of the load acting in thecircumferential direction P·sin α becomes small. This means that thetoque capacity of the roller clutch is small, so from the aspect ofmaintaining the capability to transmit torque, it is not desirable. Onthe other hand, the condition for the roller clutch 20 becoming lockedso that it is possible to transmit torque is given by tan α≦μ when μ istaken to be the coefficient of friction of the contact surface. Fromthis equation as the wedge angle α becomes large, it is seen that theroller clutch 20 does not lock and torque cannot be transmitted betweenthe pulley element 17 and the sleeve 18. In this example, the wedgeangle α is regulated to being in the range from 8 degrees to 11 degrees,so it is possible to maintain the necessary torque capacity, and sincethe locked state is possible, torque can be stably transmitted.

This kind of roller clutch 20 is also lubricated by grease that isfilled inside. The type of grease used in this case is not particularlylimited, however, it is preferred that a grease having synthetic oil asthe base oil, and a urethane type bodying or thickening agent, be usedbecause of its excellent heat resistance (high-temperature stability)and its shear stability. Particularly in the case of the roller clutch20, friction may occur at the section of contact between the rollercontact surfaces of the rollers 33 and the outer peripheral surface ofthe clutch inner ring 29 and the inner peripheral surface of the clutchouter ring 30. In this state, a large shear force is applied to thegrease, so in order to sufficiently maintain durability of the rollerclutch 20, it is necessary to use grease that has excellent shearstability. Since grease having a urethane type bodying or thickeningagent has excellent shear stability, it can be preferably used. Also,when the base oil is a synthetic oil having a low fluid point,sufficient lubrication in a wide range from the low-temperatureenvironment when starting, to a high-temperature environment afterstarting can be obtained. Therefore, it is possible to effectivelyprevent the occurrence of damage such as flaking or seizure between therolling contact surfaces of the rollers 33 and the outer peripheralsurface of the clutch inner ring 29 and the inner peripheral surface ofthe clutch outer ring 30.

The grease suitable for lubrication of the roller clutch 20 is also thegrease suitable for lubrication of the ball bearings 19. Therefore, itis possible to fill the ball bearings 19, 19 and the roller clutch 20with the same kind of grease. In that case, it is possible to preventproblems such as a degradation of greases which may occur when thegreases filled in sections are mixed to each other.

With the roller clutch 20 constructed as described above, the pulleyelement 17 and sleeve 18 have a tendency to rotate relatively in aspecified direction, or in other words, when the sleeve 18 has atendency to rotate relative to the pulley element 17 in the direction(counterclockwise in FIGS. 2 and 3) that the springs 40 are pushing therollers 33, the rollers 33 are wedged into the section of thecylindrical space where the width in the radial direction becomesnarrow. In this state, relative rotation of the sleeve 18 and the pulleyelement 17 is not possible (locked state). On the other hand, when thereis a tendency for relative rotation of the pulley element 17 and sleeve18 in the direction opposite the specified direction, or in other words,when there is a tendency for the sleeve 18 to rotate relative to thepulley element 17 in the direction opposite to the direction that thesprings 40 press the rollers 33 (clockwise direction in FIGS. 2 and 3),the rollers move back against the elastic force of the springs 40 intothe section of the cylindrical space where the width in the radialdirection is wide, and there is relative rotation of the pulley element17 and sleeve 18 (overrun state).

The function of the pulley apparatus 16 with built-in roller clutch,which is the rotation-transmission apparatus with built-in roller clutchfor starting an engine of this example constructed as described above,when the pulley apparatus 16 is used as a drive-pulley apparatus 6 foran engine-starting apparatus for the idling-stop vehicle shown in FIG.55, is as follows. First, when starting the engine, electric power flowsto the starter motor 4, and the sleeve 18 is fitted and fixed onto thatthe tip end of the rotation-drive shaft 5 and the clutch inner ring 29that is fitted and fixed onto this sleeve 18 are rotated in thecounterclockwise direction in FIGS. 2 and 3. Therefore, the rollers 33move in the counterclockwise direction of the FIGS. 2 and 3 and movetoward the section of the cylindrical space between the outer peripheralsurface of the clutch inner ring 29 and inner peripheral surface of theclutch outer ring 30 where the width in the radial direction becomesnarrow. As a result, the rolling contact surfaces of the rollers 33 arewedged into the wedge shape between the outer peripheral surface of theclutch inner ring 29 and inner peripheral surface of the clutch outerring 30, and roller clutch 20 becomes locked and power is transmittedfrom the clutch inner ring 29 to the clutch outer ring 30. In thisstate, the crankshaft 2 (see FIG. 55) of the engine 1 is rotated anddriven by way of the pulley element 17, endless belt 7 and followerpulley 3, and the engine 1 starts.

After the engine 1 starts, electric power stops flowing to the startermotor 4 and the rotation-drive shaft 5 stops. In this state, the pulleyelement 17 is rotated and driven by the crankshaft 2 of the engine 1 byway of the follower pulley 3 and endless belt 7, and the clutch outerring 30 continues to rotate on the counterclockwise direction in FIGS. 2and 3. As a result, the roller clutch 20 is in the overrun state, andthe rotation of the pulley element 17 no longer is transmitted to thesleeve 18. Therefore, when the engine 1 is operating, the starter motor4 does not become a load against the rotation of the engine 1.

When the roller clutch 20 is in the overrun state like this, the rollers33 are pressed by the column sections 36 of the clutch retainer 34 andthe springs 40, and rotate together with the clutch outer ring 30 thatis fitted into the pulley element 17. However, when the rpm of thisclutch outer ring 30 is less than the rpm necessary to start the engine1 (for example, speed after applying the transmission ratio of the belttransmission to 400 rpm to 500 rpm in the case of a gasoline engine),the centrifugal force acting on the rollers 33 is not a value that willcompress the springs 40. Also, when starting the engine 1, a force inthe same direction as the elastic force of the springs 40 is applied tothe rollers 33 from the outer peripheral surface of the clutch innerring 29. Therefore, when starting the engine, the rollers 33 definitelymove toward the section of the space between the outer peripheralsurface of the clutch inner ring 29 and the inner peripheral surface ofthe clutch outer ring 30 where the width is narrow, and the rollerclutch 20 becomes locked.

On the other hand, when the engine 1 starts and the rpm of the clutchouter ring 30 is greater than the idling rpm of the engine 1 (forexample, speed after applying the transmission ratio of the belttransmission to 700 rpm to 800 rpm in the case of a gasoline engine),not only is the connection of the roller clutch 20 broken (overrunstate), but as shown by the dashed line in FIG. 4, the rolling contactsurfaces of the rollers 33 of the roller clutch 20 become separated fromthe outer peripheral surface of the clutch inner ring 29. This will beexplained with reference to FIG. 7.

When the engine 1 is turning, a centrifugal force F₀(=m·ω²·r) acts onthe rollers 33, and the rollers 33 are pressed to the bottom of theconcave sections 32. Since the bottom surfaces of these concave sections32 are inclined, the rollers 33 have a tendency to be moved by thecomponent force F₁(=F₀·sin α) in the direction that will press thesprings 40 (compress the springs 40) (see FIGS. 2 and 3). Also, afterthe engine 1 starts, after the electric power flowing to the startermotor 4 stops, the clutch inner ring 29 also stops, so the force movingthe roller 33 in the counterclockwise direction of FIG. 3 is just theelastic force of the springs 40.

In this state, the centrifugal force F₀ increases due to the increase inrotation force, and when the magnitude of the component force F₁ becomeslarger than the elastic force of the springs 40, the rollers 33 compressthe springs 40 and move toward the deep section of the concave section32, and move from the state shown by the solid line in FIG. 4 to thestate shown by the dashed line. As a result, the rolling contactsurfaces of the rollers 33 separate from the outer peripheral surface ofthe clutch inner ring 29. In this state, the heat of friction thatoccurs inside the roller clutch 20 is suppressed to a minimum eventhough the engine 1 is turning at high speed, and as described above,this makes it possible to improve the durability of the roller clutch 20and the adjacent ball bearings 19. Of course, it is also possible toprevent damage to the roller clutch 20 itself due to abnormal wear,seizure or the like.

In order for the rolling contact surfaces of the rollers 33 to actuallybecome separated from the outer peripheral surface of the clutch innerring 29 after the engine starts in this way, it is preferable that thewedge angle α be set near the upper limit of the range from 8 degrees to11 degrees, that is 9°30′ to 10°30′. The reason for this is, that thelarger the wedge angle α is, the larger the component force F₁ of thecentrifugal force F₀ becomes, and thus it is easier to compress thesprings 40 and for the rolling contact surfaces of the rollers 33 tobecome separated from the outer peripheral surface of the clutch innerring 29.

On the other hand, in the case where the pulley apparatus 16 withbuilt-in roller clutch is installed in the auxiliary rotation-drivesection of an automobile, the wide range of operating temperature mustbe taken into consideration. In other words, when used at lowtemperature, there are times when it is not possible to increase thewedge angle α so much in order to securely reach the locked state evenwhen it becomes difficult for the rollers 33 to become wedged in thespace between the outer peripheral surface of the clutch inner ring 29and the inner peripheral surface of the clutch outer ring 30 due to theeffect of the fluidity of the grease. In this case, the wedge angle α isset near the lower limit of the range 8 degrees to 11 degrees.

Moreover, in the case of this example, the depth of the concave sections32 must be adequately regulated in order for the rolling contactsurfaces of the rollers 33 to separate from the outer peripheral surfaceof the clutch inner ring 29 after the engine starts as described above.In other words, when the rollers 33 are located in the deepest sectionof the concave sections 32 as shown by the dashed line in FIG. 4, thesize of the gap δ₂₀ that exists between the rolling contact surfaces ofthe rollers 33 and the outer peripheral surface of the clutch inner ring29 is larger than the size of the radial gap δ₁₉ of the ball bearings 19(δ₂₀<δ₁₉). It should be note that the gap δ₂₀ is a radius dimension andthe radial gap δ₁₉ is a diameter dimension. Therefore, even when thecenter axis of the clutch inner ring 29 and the center axis of theclutch outer ring 30 are eccentric with respect to each other due to theradial gap δ₁₉ of the ball bearings 19 (by just the amount of thisradial gap δ₁₉), the rolling contact surfaces of all of the rollers 33will securely separate from the outer peripheral surface of the clutchinner ring 29 after the engine starts.

The rpm of the clutch outer ring 30 at which the rolling contactsurfaces of the rollers 33 will separate from the outer peripheralsurface of the clutch inner ring 29 is regulated in consideration of thedurability of the roller clutch 20, and it is preferably set as low apossible such that the engagement of roller clutch 20 is secured whenstarting the engine 1. However, in this case, taking into considerationthe degradation over time of the springs 40, in order that theengagement of roller clutch 20 is securely made even when the elasticforce of the springs 40 decreases a little, for example it is consideredthat, in the case of a new part, the rpm of the clutch outer ring 30 isset to a value such that the rolling contact surfaces separate from theouter peripheral surface when the rpm of the crankshaft 2 of the engine1 is from 1000 rpm to 1500 rpm. In this case, in the initial state, whenthe engine 1 is idling, the rolling contact surfaces come in frictioncontact with the outer peripheral surface, however, the contact pressureat the rubbing surfaces in this case becomes very small due to theeffect of the centrifugal force. Also, since the rpm itself is low, thefriction heat and wear that occur on the rubbing surfaces is kept to aminimum.

Next, FIG. 8 shows a second example of the embodiment of the invention.In this example, the independent clutch inner ring 29 is omitted fromthe construction of the first example shown in FIG. 1, and the middlesection of the sleeve 18 a is made to function as the clutch inner ringof the roller clutch 20 a. In order for this, in this example, thesurface layer (the diagonal cross section shown in FIG. 8) of thelarge-diameter section 21 formed in the middle section of the sleeve 18a is hardened by heat treatment such as induction heat treatment orcarbonitriding, and the hardness of the surface of this large-diametersection 21 is made to be Hv 500 or more.

By using this kind of construction, this example does not require anindependent clutch inner ring 29, and so it is possible to simplify partmanufacturing, part management and assembly, and thus it is possible toreduce costs. Also, since the number of parts is decreased, assemblyerror can be reduced, and thus it is possible to improve performance dueto the improvement of precision of the pulley apparatus with built-inroller clutch. In order to prevent deformation of the rolling contactsurfaces of the rollers 33 when pressed hard, surface hardening isperformed for the surface layer of the large-diameter section 21 only,so the section near the inner peripheral surface of the sleeve 18 a isleft as is without being quench-hardened. As a result, processing worksuch as forming a male screw or spline on the inner peripheral surfaceof the sleeve 18 a can be performed easily. Therefore, there is nolimitation in the structure where the sleeve 18 a is fitted onto the endsection of the rotation-drive shaft 5 (see FIG. 55). When applying theinvention, the sleeve can also be omitted, and the outer peripheralsurface of the rotating shaft, such as the rotation-drive shaft 5,itself can be used as the inner race track for clutch that comes incontact with the rolling contact surfaces of the rollers of the rollerclutch. In this case, the inner race of the support bearings is fitteddirectly onto the outer peripheral surface of the rotating shaft, suchas the rotation-drive shaft 5.

In each of the examples described above, the case of installing andusing the rotation-transmission apparatus with built-in roller clutch inthe engine starting apparatus for an idling-stop vehicle was explained,however, application of the examples described above is not limited toan engine starting apparatus. Use of the construction of the examplesdescribed above is effective in applications where the rpm of therotating members in the overrun state is faster than the rpm of therotating members in the locked state, and where the operating time inthe overrun state is long. As an example of this kind of application, isthe auxiliary drive apparatus such as a compressor that is installed inan idling-stop vehicle.

Furthermore, when applying this invention, the construction of each ofthe components of the rotation-drive-transmission apparatus withbuilt-in roller clutch can be changed as long at the elements given inthe claims of this disclosure are satisfied. First, in the case of thethird example of the invention shown in FIG. 9, a cylindrical shapedmember that does not have bent sections on both ends is used as theclutch outer ring 30 a. Together with this, a collar section 47 thatprotrudes outward in the radial direction is formed around the outerperipheral surface on the end section of the clutch retainer 34 a isheld between the clutch outer ring 30 a and the outer race 24 of theball bearing 19 to regulate the position in the axial direction of theclutch retainer 34 a.

Next, in the case of a fourth example shown in FIG. 10, a member onwhich an inward facing collar section 39 is formed on only one endsection (left end section in FIG. 10) is used as the clutch outer ring30 b. In this example, the position in the axial direction of the clutchouter ring 30 b is regulated by being held between the outer races 24 ofthe pair of ball bearings 19. Also, the position in the axial directionof the clutch retainer 34 is regulated by the inward facing collarsection 39 and one of the outer races 24 (the race on the right side inFIG. 10).

Next, in the case of a fifth example shown in FIG. 11, a cylindricalmember that does not have bent sections on both ends is used as theclutch outer ring 30 a. Also, the position in the axial direction of theclutch retainer 34 is regulated by the outer races 24 of the pair ofball bearings 19.

Next, in the case of a sixth example shown in FIG. 12, a cylindricalmember that does not have bent sections on both ends is used as theclutch outer ring 30 a. Also, the outer peripheral surface of the sleeve18 b is a simple cylindrical surface that does not have a steppedsection in the middle. The clutch inner ring 29 is tightly fitted ontothe middle section in the axial direction of this sleeve 18 b throughinterference fit.

Next, in the case of a seventh example shown in FIG. 13, the innerperipheral surface in the middle section of the pulley element 17 a hasa smaller diameter than on both ends, and the cam surface 31 is formeddirectly on this inner peripheral surface in the middle section.Corresponding to this, a collar section 47 is formed around the outerperipheral surface on one end of the clutch retainer 34 a to protrudeoutward in the radial direction, and held between the end surface of thesection in the middle section where the diameter becomes smaller and theouter race 24 of the ball bearing 19, so as to regulate the position inthe axial direction of the clutch retainer 34 a.

Next, in the case of an eighth example shown in FIG. 14, the innerperipheral surface in the middle section of the pulley element 17 a hasa smaller diameter than on both ends, and the cam surface 31 is formeddirectly on this inner peripheral surface in the middle section. Also,the position in the axial direction of the clutch retainer 34 isregulated by the outer races 24 of the pair of ball bearings 19.

Next, in the case of a ninth example shown in FIG. 15, an end cap 44 theis made of synthetic resin or metal and formed into a petri-dish shapeis fitted onto the outside end (left end in FIG. 15) of the pulleyelement 17, and it prevents foreign matter from getting into the spacewhere the ball bearings 19 and roller clutch 20 b are housed.

Next, in the case of a tenth example shown in FIG. 16 the outer edgesection of an end cap 44 a is fitted into an attachment groove that isformed on the inner peripheral surface on the outside end of the outerrace 24 of the outside (left side in FIG. 16) ball bearing 19, and itprevents foreign matter from getting into the space where the ballbearings 19 and roller clutch 20 b are housed.

Next, in the case of an eleventh example shown in the FIG. 17, the outeredge section of an end cap 44 b is fitted into a cut-out section 45 thatis formed on the outside end surface (surface on the left end in FIG.17) of the pulley element 17, and it prevents foreign matter fromgetting into the space where the ball bearings 19 and roller clutch 20 bare housed.

Next, in the case of a twelfth example shown in FIG. 18 the outer edgesection of an end cap 44 c is fitted into a dovetail-groove shapedattachment groove 46 that is formed on the outside end surface (surfaceon the left end in FIG. 18) of the pulley element 18, and it preventsforeign matter from getting into the space where the ball bearings 19and roller clutch 20 b are housed. In this example, the dimension in theaxial direction of the part of the pulley element 17 that is locatedfurther outside in the radial direction than the end cap 44 c isdecreased.

A summary of the construction of the pulley apparatus with built-inroller clutch 16 of the first thru twelfth examples described above isas follows.

This pulley apparatus with built-in roller clutch 16 transmits poweronly in a specified direction between the circular-ring-shaped pulley,which has an endless belt that runs around its outer peripheral surfaceand rotates only in the specified direction during operation, and therotating shaft that is inserted through the center section of thispulley and rotates only in this specified direction during operation.

Also, the pulley apparatus with built-in roller clutch 16 comprises: apair of support bearings, which are located in the circular-ring-shapedspace between the inner peripheral surface of the pulley and the outerperipheral surface of the rotating shaft and spaced apart from eachother in the axial direction, and a roller clutch that is located inthis circular-ring shaped space between this pair of support bearings.

Moreover, this roller clutch engages with the rotating shaft when itrotates in the specified direction and transmits power to the pulleyfrom the rotating shaft, however, when the pulley is rotating in thespecified direction faster than the rotating shaft, the roller clutchidles and does not transmit power from the pulley to the rotating shaft.

Furthermore, a cam surface for moving the plurality of rollers of theroller clutch in the radial direction of the pulley is formed around theinner peripheral surface of the pulley or around the inner peripheralsurface of a clutch outer ring that is fitted inside this pulley, andthe outer peripheral surface of the rotating shaft or the outerperipheral surface of a clutch inner ring that is fitted onto therotating shaft is a cylindrical surface.

With the kind of pulley apparatus with built-in roller clutch 16 of thefirst thru twelfth examples, when the rotating shaft is stopped, or whenthe pulley rotates faster than the rotating shaft, not only is theconnection of the roller clutch open, but the rolling contact surfacesof the plurality of rollers of the roller clutch are separated from theouter peripheral surface of the rotating shaft or the outer peripheralsurface of the clutch inner ring that fits around the rotating shaft.Therefore, when the pulley is rotating, it is possible to suppress to aminimum the friction heat that occurs inside the roller clutch, and thusit is possible to improve the durability of the roller clutch and theadjacent support bearings.

Next, FIG. 19 shows a reference example that is outside the range ofthis invention, and FIG. 20 shows a thirteenth example of the invention.Both of these examples were invented for the purpose of sufficientlymaintaining the durability of a rotation-transmission apparatus withbuilt-in roller clutch, which include that for starting an engine,however, more particularly for the purpose of solving the followingproblems. The following explanation explains the case in which therotation-transmission apparatus with built-in roller clutch is used asan auxiliary drive apparatus, however, it is the same as the case inwhich it is used for starting an engine.

That is, the use of a pulley apparatus with a built-in one-way clutchhas been known conventionally as a pulley apparatus for drivingauxiliary devices such as an alternator (for example, refer to patentdocuments 1 and 3). FIGS. 21 and 22 show a first example of theconventional construction of a pulley apparatus with a built-in rollerclutch, which is one type of this kind of pulley-apparatus with built-inone-way clutch. This pulley-apparatus with built-in one-way clutchcomprises a sleeve 18 b and a pulley element 17 that are concentric witheach other. Also, there is a roller clutch 8, which is a one-way clutch,and a pair of support bearings 48 located between the outer peripheralsurface of the sleeve 18 b and the inner peripheral surface of thepulley element 17.

The sleeve 18 b is has a generally cylindrical shape, and it is fittedand fastened onto the rotating shaft of the auxiliary device such as analternator, and it rotates with this rotating shaft. On the other hand,the pulley element 17 also has a generally cylindrical shape, and thecross-sectional shape in the width direction of the middle sectionaround its outer peripheral surface is wave shaped, around which part ofan endless belt, called a poly V-belt, is placed. Also, there is aroller clutch 8 located in the middle section in the axial direction ofthe circular-ring shaped space that exists between the outer peripheralsurface of the sleeve 18 b and the inner peripheral surface of thepulley element 17, and also on both ends in the axial direction of thissame space there is a pair of support bearings 48 such that they arelocated on both sides in the axial direction of the roller clutch 8. Ofthese, the pair of support bearings 48 support radial loads that areapplied to the pulley element 17, and make it possible for the pulleyelement 17 to rotate relative to the sleeve 18 b. In the example shownin the drawings, deep-groove type ball bearings are used for thesesupport bearings 48.

Also, only when there is a tendency for relative rotation between thepulley element 17 and sleeve 18 b in a specified direction, the rollerclutch 8 transmits rotation force between the pulley element 17 and thesleeve 18 b. This roller clutch 8 comprises: an inner member, which is aclutch inner ring 29 made of steel plate, and a outer member, which is aclutch outer ring 30 made of steel plate, a plurality of steel rollers33, a clutch retainer 34 made of synthetic resin, and elastic members(not shown in the figures), which are springs. Of these, the clutchinner ring 29 is tightly fitted onto the outer peripheral surface in themiddle section of the sleeve 18 b, and the clutch outer ring 30 istightly fitted into the inner peripheral surface in the middle sectionof the pulley element 17, respectively through interference fit. Theinner peripheral surface in the middle section of the clutch outer ring30 is a cylindrical surface 49, and the outer peripheral surface of theclutch inner ring 29 is a cam surface 50. In other words, a plurality ofconcave sections 51 called ramp sections are formed on the outerperipheral surface of the clutch inner ring 29 such that they are evenlyspaced around in the circumferential direction, and the outer peripheralsurface of this clutch inner ring 29 functions as a cam surface 50.

Moreover, in the cylindrical space between this cam surface 50 and thecylindrical surface 49, there are a plurality of rollers 33, and aclutch retainer 34 (omitted in FIG. 22) that holds the rollers 33 suchthat they can freely roll and move a little in the circumferentialdirection. The rollers 33 are located in sections in alignment with theconcave sections 51. Also, by attaching the inner peripheral edge of theclutch retainer 34 to part of the cam surface 50, it is prevented fromrotating relative to the clutch inner ring 29. In other words, theclutch retainer 34 and clutch inner ring 29 rotate in synchronization.Moreover, there are springs (not shown in the figure) between the clutchretainer 34 and the rollers 33 so as to press the rollers 33 in the samedirection in the circumferential direction (right direction in FIG. 22)toward the shallow side of the concave sections 51.

In the case of this roller clutch 8, when there is a tendency for theclutch outer ring 30 to rotate in the clockwise direction (to the right)in FIG. 22 with respect to the clutch inner ring 29, as shown in thesame figure, the rollers 33 become wedged between the cylindricalsurface 49 and the bottom surfaces of the concave sections 51 of the camsurface 51. As a result, rotation force begins to be transmitted betweenthe clutch outer ring 30 and clutch inner ring 29, and the clutch outerring 30 and clutch inner ring 29 rotate together. This state is calledthe locked state. On the other hand, when there is a tendency for theclutch outer ring 30 to rotate in the counterclockwise direction in FIG.2 (rotate to the left) with respect to the clutch inner ring 29, therollers 33 move against the elastic force of the springs toward the deepsection of the concave sections 51 (sections on the left side in FIG.22) and the pressure at the points of contact between the rollingcontact surfaces of the rollers 33 and the cylindrical surface 49droves. As a result, rotation force stops being transmitted between theclutch outer ring 30 and the clutch inner ring 29, and the clutch outerring 30 and clutch inner ring 29 rotate relative to each other. Thisstate is called the overrun state.

In the pulley apparatus with built-in roller clutch constructed asdescribed above, the sleeve 18 b is fitted and fastened onto the endsection of the rotating shaft of an auxiliary device such as analternator, and an endless belt runs around the outer peripheral surfaceof the pulley element 17. This endless belt also runs around the drivepulley that is fastened to the end section of the engine crankshaft, andis driven by the rotation of this drive pulley. With the pulleyapparatus with built-in roller clutch is assembled in this state, whenthe running speed of the endless belt is constant or has a tendency toincrease, the roller clutch 8 becomes engaged (lock state), and rotationpower is freely transmitted from the pulley element 17 to the rotatingshaft. However, when the running speed of the endless belt decreases,the connection of the roller clutch 8 is broken (overrun state) and thepulley element 17 and rotating shaft freely rotate relative of eachother. As a result, even when the rotational angular speed of thecrankshaft changes, it is possible to prevent rubbing between theendless belt and the pulley element 17, and thus together with beingable to prevent the generation of noise called crying and a drop in thelife of the endless belt due to friction, it is possible to prevent adrop in the power-generating efficiency of the alternator.

In the case of the pulley apparatus with built-in roller clutch shown inFIGS. 21 and 22 described above, the cylindrical surface 49 of theroller clutch 8 is located around the inner peripheral surface of theclutch outer ring 30, and the cam surface 50 is located around the outerperipheral surface of the clutch inner ring 29. However, the locationsin the radial direction of the cylindrical surface and cam surface maybe opposite as in the case of the second example of prior constructionof a pulley apparatus with built-in roller clutch shown in FIG. 23(refer to Patent Document No. 4). In other words, in the case of theroller clutch 8 a shown in FIG. 23, the cylindrical surface 49 a islocated around the outer peripheral surface of the clutch inner ring 29a, and the cam surface 50 a is located around the inner peripheralsurface of the clutch outer ring 30 c. Moreover, in the case of theconstruction of the roller clutches 8, 8 a described above, thecylindrical surfaces 49, 49 a and cam surfaces 50, 50 may be formeddirectly on the inner peripheral surface of the pulley element 17 andthe outer peripheral surface of the sleeve 18 b (refer to PatentDocument No. 4).

In order to securely achieve the locked state of the roller clutch 8, 8a described above, for example, as shown in FIG. 24, when the rollers 33are pushed into the section where the width of the space between thecylindrical surface 49 a and the cam surface 50 a (wedge angle α) isnarrow, it is necessary that slipping does not occur at the points ofcontact between the rolling contact surfaces of the rollers 33 and thecylindrical surface 49 a. Here, the force P that the rollers 33 receivefrom the cylindrical surface 49 a will be considered. This force P isthe combination of the friction force [P·sin α] that acts at the pointsof contact between the rolling contact surfaces of the rollers 33 andthe cylindrical surface 49 a, and the vertical resistance force [P·cosα] that acts on the rollers 33 from the cylindrical surface 49 a. Whenthe coefficient of static friction at the point of contact is taken tobe μ, then the maximum static friction force at the point of contact isμμP·cos α]. Therefore, the condition to prevent any slipping between therolling contact surfaces of the rollers 33 and the cylindrical surface49 a is [P·sin α≦μP·cos α] (in other words, the friction force [P·sin α]acting at this point of contact is up to the maximum static frictionforce [μP·cos α]). Also, from this condition [P·sin α≦μP·cos α], it canbe seen that the larger the coefficient μ of static friction at thepoint of contact is, the more difficult it is for slipping to occur atthe point of contact.

On the other hand, the vertical resistance force that the rollers 33receive from the cam surface 50 a becomes larger as the force P becomeslarger. Also, as the vertical resistance force that the rollers 33receive from the cam surface 50 a becomes large, the maximum frictionforce at the points of contact between the rolling contact surfaces ofthe rollers 33 and the cam surface 50 a becomes large, and it becomesdifficult for slipping to occur at these points of contact. However, ifslipping does not occur at the points of contact between the rollingcontact surfaces of the rollers 33 and the cylindrical surface 49 a (thecondition [P·sin α≦μP·cos α] described above), the force P becomeslarger as the rotation force to be transmitted by the roller clutch 8, 8a becomes larger. Therefore, by making the coefficient μ of staticfriction at the points of contact between the rolling contact surfacesof the rollers 33 and the cylindrical surface 49 a large, it is possiblefor the force P to become larger, and as a result, it is more difficultfor slipping to occur at the points of contact between the rollingcontact surfaces of the rollers 33 and the cam surface 50 a.

From this it can be seen that by making the coefficient μ of staticfriction at the points of contact between the rolling contact surfacesof the rollers 33 and the cylindrical surface 49 a large, it becomesdifficult for slipping to occur at the points of contact between therolling contact surfaces of the rollers 33 and the cylindrical surface49 a, and at the points of contact between the rolling contact surfacesof the rollers 33 and the cam surface 50 a, and as a result it is easyto achieve the locked state of the roller clutch 8, 8 a.

Therefore, employing a method of regulating the condition of lubricationat the points of contact between the rolling contact surfaces of therollers 33 and the cylindrical surface 49 a is considered as a methodfor increasing the coefficient μ of static friction at these points ofcontact. However, since it is difficult to regulate the condition oflubrication at the points of contact, employing this method isdifficult.

Therefore, increasing the roughness of the rolling contact surfaces ofthe rollers 33 and the cylindrical surface 49 a, in contact with eachother, is considered as another method for increasing the coefficient μof static friction at these points of contact. However, the rollingcontact surfaces of the rollers 33 and the cylindrical surface 49 a aremetal surfaces. Also, there is rubbing between the rolling contactsurfaces of the rollers 33 and the cylindrical surface 49 a duringoverrun. Therefore, if the roughness of the rolling contact surfaces ofthe rollers 33 and the cylindrical surface 49 a increased, the frictionforce acting on the points of rubbing between these surfaces duringoverrun increases, and it is easy for wear or seizure to occur at thepoints of rubbing.

The construction of the first reference example and the thirteenthexample shown in FIGS. 19 and 20 take into consideration the problemmentioned above, and together with making it possible to securelyachieve the locked state of the one-way clutch, the construction makesit difficult of wear or seizure to occur at the points of rubbing duringoverrun of the one-way clutch.

First, the first reference example shown in FIG. 19 is an example of apulley apparatus with built-in roller clutch that is fastened to the endof the rotating shaft of an alternator, and the feature of thisconstruction is the characteristics of the cylindrical surface 49 b ofthe roller clutch 8 b, that is one-way roller clutch. The constructionand function of the other parts are the same as those of the firstexample of prior construction of the pulley apparatus with built-inroller clutch shown in FIGS. 21 and 22 and described above, so anyredundant figures and explanations will be omitted or simplified, andthis explanation will center on the characteristics of this example.

The roller clutch 8 b of the pulley apparatus with built-in one-wayclutch of this example comprises a cylindrical surface 49 b that islocated around the inner peripheral surface of the clutch outer ring 30d, and a cam surface 50 that is located around the outer peripheralsurface of the clutch inner ring 29. In this example, the pulleyapparatus with built-in one-way clutch is fastened to the end of therotating shaft of an alternator, and it is basically operated in thelocked state, and the amount of time it is operated in the overrun stateis very short compared with the overall operating time. Taking this intoconsideration, with the roller clutch 8 b that is assembled in thepulley apparatus with built-in one-way clutch of this example in orderto easily achieve the locked state during operation of the engine, andin order that the plurality of rollers 33 are not moved into the concavesections of the cam surface by the centrifugal force due to rotation, asmentioned above, the cam surface 50 is located around the outerperipheral surface of the clutch inner ring 29.

Moreover, in this example, a chemical conversion coating, specificallymanganese phosphate layer 52 is formed on the cylindrical surface 49 b.The process for forming this kind of manganese phosphate layer 52 issummarized below. Under specified temperature conditions, the innerperipheral surface of the clutch outer ring 30 d which is the basematerial, is immersed in a manganese phosphate saline solution. As aresult, isolated phosphoric acid occurs due to the first dissociation ofthe manganese phosphate saline solution, and the iron on the innerperipheral surface (metal surface) of the clutch outer ring 30 ddissolves. Together with this, the concentration of the hydrogen ions onthis metal surface decreases, and while dissociation equilibrium of themanganese phosphate saline solution transits on this metal surface,crystals of insoluble manganese phosphate salt are deposited on thismetal surface. The deposited crystals become the manganese phosphatelayer 52.

In the case of the pulley apparatus with built-in one-way clutchconstructed as described above, the manganese phosphate layer 52 isformed on the cylindrical surface 49 b. The surface of this manganesephosphate layer 52 is rough, so it is possible to increase thecoefficient of static friction at the points of contact between thecylindrical surface 49 b having this manganese phosphate layer 52 andthe rolling contact surfaces of the plurality of rollers 33. Therefore,when the roller clutch 8 b is in the locked state, it is difficult forslipping to occur at the points of contact between the cylindricalsurface 49 b and the rolling contact surfaces of the rollers 33.Therefore, in the case of this example, it is possible to securelyachieve the locked state.

On the other hand, when the roller clutch 8 b is in the overrun state,the manganese phosphate layer 52 prevents metal contact between thecylindrical surface 49 b and the rolling contact surfaces of the rollers33. Also, lubricant is held between the crystal grains of the manganesephosphate layer 52, so there is good lubrication at the points ofrubbing between the cylindrical surface 49 b and the rolling contactsurfaces of the rollers 33 due to this lubricant. Therefore, duringoverrun of the roller clutch 8 b, it is difficult for wear or seizure tooccur at the points of rubbing.

Next, FIG. 20 shows a thirteenth example of the embodiment of theinvention corresponding to claims 1 and 6. This example is arotation-transmission apparatus with built-in roller clutch for startingan engine and is attached to the end of the drive shaft that is rotatedand driven by a starter motor. Similar to the first reference exampleshown in FIG. 19, the feature of this example is in the characteristicsof the cylindrical surface 49 c of the one-way roller clutch 8 c. Theconstruction and function of the other parts are substantially the sameas those of the first and second examples of prior art construction ofthe pulley apparatus with built-in roller clutch shown in FIGS. 21 and23 and described above, so any redundant figures and explanations willbe omitted or simplified, and this explanation will center on thecharacteristics of this example.

The roller clutch 8 c of the rotation-transmission apparatus withbuilt-in roller clutch for starting an engine of this example comprisesa cylindrical surface 49 c that is located around the outer peripheralsurface of the clutch inner ring 29 b, and a cam surface 50 a that islocated around the inner peripheral surface of the clutch outer ring 30a. Also, there is the manganese phosphate layer 52 that is a chemicalconversion coating formed on the cylindrical surface 49 c. In therotation-transmission apparatus with built-in roller clutch of theexample, constructed as described above, a sleeve 18 b (see FIG. 21) isfitted and fastened onto the end of the drive shaft of the startermotor, and an endless belt runs around the outer peripheral surface ofthe pulley element 17 (see FIG. 21). This endless belt also runs arounda follower pulley that is fastened to the end of the engine crankshaft.

Also, when starting the engine, electric power flows to the startermotor that then rotates and drives the rotation-transmission apparatuswith built-in roller clutch, and rotates and drives the crankshaft byway of the endless belt and follower pulley. In other words, at thistime, the roller clutch 8 c is in the locked state and transmits powerfrom the drive shaft of the starter motor to the endless belt. Also,after the engine has started the roller clutch 8 c changes in theoverrun state such that drive shaft of the starter motor does not turneven though the endless belt is running with the rotation of thecrankshaft. Therefore, the starter motor does not become a resistiveload against the operation of the engine, and durability of the startermotor not decreased. With this kind of construction, it is possible toimmediately start the engine by just starting the starter motor.Therefore, by installing this kind of construction in an idling stopvehicle, it is possible to start moving again in a short time after anidling stop, and so there is no feeling of discomfort when the operatorstarts the engine again.

As described above, the rotation-transmission apparatus with built-inroller clutch for starting an engine of this example is operated most ofthe time in the overrun state and the amount of time that it is operatedin the locked state is very short when compared with the overalloperating time. Taking this into consideration, the cam surface 50 a islocated around the inner peripheral surface of the clutch outer ring 30c as mentioned above in order to make the plurality of rollers 33retract into the concave sections 51 of the cam surface 50 a by thecentrifugal force caused by rotation when the roller clutch 8 c that isassembled in this rotation-transmission apparatus with built-in rollerclutch for starting an engine is in the overrun state when the enginestarts, so that rubbing is prevented between the rolling contactsurfaces of the rollers 33 and the cylindrical surface 49 c.

In the case of the rotation-transmission apparatus with built-in rollerclutch for starting an engine of this example constructed as describedabove, a manganese phosphate layer 52 is formed on the cylindricalsurface 49 c of the roller clutch 8 c, so as in the case of the firstreference example shown in FIG. 19 described above, it is possible forthis roller clutch 8 c to securely achieve a locked state, and it isdifficult for wear and seizure to occur in the rubbing section betweenthe cylindrical surface 49 c and the rolling contact surfaces of theplurality of rollers 33 when in the overrun state, and thus it ispossible to improve durability. Particularly, in the case of thisembodiment, the roller clutch 8 c is in the locked only for a short timewhen starting the engine, and after the engine starts the roller clutch8 c is in the overrun state as long as the engine is running and thereis no rubbing between the rolling contact surfaces of the rollers 33 andthe cylindrical surface 49 c. Therefore, it is possible to moreeffectively obtain the effect of making it difficult for wear or seizureto occur at the rubbing sections during overrun.

In the examples described above, of the rolling contact surfaces of therollers and the cylindrical surface of the roller clutch, a chemicalconversion layer was formed only on the cylindrical surface, however, itis also possible to form this chemical conversion coating on just therolling contact surfaces of the rollers, or to form it on both therolling contact surfaces of the rollers and the cylindrical surface. Inthese cases, it is possible to easily achieve the locked state, and tomake it difficult for wear or seizure to occur at the rubbing sectionsduring overrun. Also, in addition to the roller clutch described above,the first reference example shown in FIG. 19 and the thirteenth exampleshown in FIG. 20 can also be applied to a one-way clutch havingdifferent construction such as a cam clutch like a sprag clutch.

The first reference example and the thirteenth example shown in FIGS. 19and 20 are for the improvement of the pulley apparatus with built-inone-way clutch that is fastened to the end of the rotating shaft such asin the alternator or compressor of an auxiliary device for anautomobile, the starter motor of the starting apparatus for anautomobile, or the auxiliary-drive motor of an idling-stop vehicle, andthe one-way clutch that is assembled and used in this pulley apparatuswith built-in one-way clutch. Also, a summary of the construction of theone-way clutch (first, second one-way clutch) and the pulley apparatuswith built-in one-way clutch (first to third pulley apparatus withbuilt-in one-way clutch) shown in the first reference example andthirteenth example is given below.

First, the first one-way clutch comprises: an inner member, an outermember that is located around the outside of the inner member such thatit is concentric with the inner member, and a plurality of engagingmembers that are located between the outer peripheral surface of theinner member and the inner peripheral surface of the outer member. Also,at least one of the outer peripheral surface of the inner member and theinner peripheral surface of the outer member is a cylindrical surface.Moreover, only when there is a tendency for relative rotation in aspecified direction of the inner member and outer member, is rotationforce transmitted between the inner member and outer member by way ofthe engaging members that engage with the outer peripheral surface ofthe inner member and the inner peripheral surface of the outer member.

Particularly, in the first one-way clutch described above, a chemicalconversion coating such as a manganese phosphate layer is formed on atleast one of the surface of the engagement members and the cylindricalsurface.

Moreover, similar to the roller clutches 8, 8 a described above andshown in FIGS. 21 to 23, the second one-way clutch (roller clutch)comprises: an inner member, an outer member that is located around theoutside of the inner member such that it is concentric with the innermember, a cam surface, a cylindrical surface, a plurality of rollers, aretainer, and elastic members. Of these, the cam surface is locatedaround one of the outer peripheral surface of the inner member and theinner peripheral surface of the outer member, and it has a concavesections located a plurality of locations in the circumferentialdirection. Also, the cylindrical surface is located around the other ofthe outer peripheral surface of the inner member and the innerperipheral surface of the outer member. The rollers are located in thecylindrical space between the cylindrical surface and the cam surface inthe sections that match up with the concave sections. The retainer issupported in the cylindrical space such that it cannot rotate withrespect to the member around which the cam surface is formed, and itholds the rollers such that they can rotate freely and can move a littlein the circumferential direction. The elastic members are locatedbetween the retainer and the rollers, and press these rollers in thesame circumferential direction.

Particularly, in the second one-way clutch (roller clutch) describedabove, a chemical conversion coating such as a manganese phosphate layeris formed on at least one of the rolling contact surface of the rollersand the cylindrical surface.

Also, the first pulley apparatus with built-in one-way clutch comprises:a cylindrical pulley that fits around the rotating shaft such that it isconcentric with the rotating shaft, support bearings, and a one-wayclutch. Of these, the support bearings are located between the outerperipheral surface of the rotating shaft and the inner peripheralsurface of the pulley, and they supports radial loads that act betweenthe rotating shaft and pulley, and make it possible relative rotation ofthe rotating shaft and pulley possible. Moreover, the one-way clutch islocated between the outer peripheral surface of the rotating shaft andthe inner peripheral surface of the pulley in the section separated inthe axial direction from the support bearings, and it transmits rotationpower between the rotating shaft and pulley only when there is relativerotation of the rotating shaft and pulley in a specified direction.

Particularly, in this first pulley apparatus with built-in one-wayclutch, this one-way clutch is either the first or second one-way clutchdescribed above.

Moreover, in the second pulley apparatus with built-in one-way clutch,the rotating shaft is a component of an alternator, and the cylindricalsurface of the one-way clutch is located around the inner peripheralsurface of the outer member, and the cam surface is located around theouter peripheral surface of the inner member.

Furthermore, in the third pulley apparatus with built-in one-way clutch,the rotating shaft is the drive shaft that is rotated and driven by astarter motor, and the cylindrical surface of the one-way clutch islocated around the outer peripheral surface of the inner member, and thecam surface is located around the inner peripheral surface of the outermember.

In the case of the first and second one-way clutches and first thruthird pulley apparatuses with built-in one-way clutches, a chemicalconversion coating, such as a manganese phosphate layer is formed on atleast one of the surface of the plurality of engagement members and thecylindrical surface of the one-way clutch. The surface of this chemicalconversion coating is rough. Therefore, it is possible to make thecoefficient of static friction at the points of contact between thesurface of the plurality of engagement members and the cylindricalsurface large. Therefore, when the one-way clutch is provided in thelocked state, it is difficult for slipping to occur at the points ofcontact between the surface of the plurality of engagement members andthe cylindrical surface, and thus it is easy to achieve the lockedstate. On the other hand, when the one-way clutch is in the overrunstate, the chemical conversion coating makes it possible to preventmetallic contact between the surfaces of the plurality of engagementmembers and the cylindrical surface. Together with this, lubricant isheld between the crystal grains of this chemical conversion coating, sothis lubricant makes it possible to have good lubrications at thesections of rubbing between the surface of the plurality of engagementmembers and the cylindrical surface. Therefore, when the one-way clutchis in the overrun state, it is difficult for wear and seizure to occurat these rubbing sections. In this way, together with being able tosecurely achieve the locked state, it is possible to make it difficultfor wear and seizure to occur in the areas of rubbing during the overrunstate, and thus it is possible to improve reliability and durability.

Next, FIGS. 25 to 27 shows a fourteenth example of the embodiment of theinvention, FIGS. 28 and 29 show a fifteenth example of the embodiment ofthe invention, FIG. 30 shows a sixteenth example of the embodiment ofthe invention, and FIG. 31 shows a seventeenth example of the embodimentof the invention. Each example was invented to sufficiently maintain thedurability of a rotation-transmission apparatus with built-in rollerclutch for starting an engine, and more specifically were invented withthe object of solving the following problems.

That is, conventionally a roller clutch as disclosed in Patent DocumentNo. 4, for example, has been known as a one-way clutch having thefunction of allowing transmission of rotation in only a specifieddirection between a pair of concentrically placed members. FIGS. 32 and33 show a second and third example of the prior art construction of aknown roller clutch. First, the second example of the prior artconstruction of a known roller clutch shown in FIG. 32 comprises: aninner ring 9 a or inner member, and an outer ring 10 a or outer member(see FIG. 33) that are concentric with each other, a retainer 11 a thatis located between the outer peripheral surface of the inner ring 9 aand the inner peripheral surface of the outer ring 10 a, a plurality ofrollers 12 and the same number of springs 13 as rollers 12. The innerperipheral surface of the outer ring 10 a is a cam surface 53 (explainedlater using FIG. 33) having a plurality of concave sections 14 that arecalled ramp sections, and the outer peripheral surface of the inner ring9 a is a simple cylindrical surface. Moreover, the retainer 11 acomprises a pair of circular-ring shaped rim sections 54 and columnsections 55 that are located at a plurality of locations in thecircumferential direction to connect the rim sections 54 at thelocations. Also, the convex sections 56 are formed around the outerperipheral edge of the rim sections 54 and engaged with theaforementioned concave sections 14, so that relative rotation of theretainer 11 a with respect to the outer ring 10 a is prevented. In otherwords, the retainer 11 a and outer ring 10 a are made to rotate insynchronization.

Moreover, the springs 13 are formed by bending spring steel plate into atriangular hook shape. Also, protruding support sections 57 a, 57 b areformed on the outside surface of in the radial direction of the columnsections 55 in the axially middle section of the retainer 11 a, at threelocations in the axial direction and the base sections 58 of the springs13 are supported by these protruding support sections 57 a, 57 b. Inother words, by supporting the base section 58 of the spring 13 betweenthe pair of protruding support sections 57 a that are formed near bothends in the axial direction of the column sections 55, and the oneprotruding support section 57 b that is located in the middle section inthe axial direction thereof, the base sections 58 are supported by theprotruding sections 57 a, 57 b. Also, these springs 13 press the rollers12 in the same circumferential direction toward the shallow side of theconcave sections 14.

Furthermore, in the case of the third example of prior art constructionof a roller clutch shown in FIG. 33, the rollers 12 are held between thecam surface 53 of the outer ring 10 a and the outer peripheral surfaceof the inner ring 9 a, and in the state when these rollers 12 roll alongthe concave sections 14 to the deep side of the concave sections 14, theposition of the tip edge of the springs 13 comes in contact with thefront ends of the rolling contact surfaces of the rollers 12 (theposition indicated by the point P in FIG. 33) in the direction ofmovement of the center axis O of the rollers 12 (direction indicated bythe arrow X in FIG. 33). Therefore, in this example, in this state, thedirection that the springs 13 press the rollers 12 (the directionindicated by the arrow Y in FIG. 33) and the direction of movement ofthe center axis O are located on the same line.

In the case of the conventionally known roller clutches constructed asdescribed above, when there is a tendency for the inner ring 9 a torotate relative to the outer ring 10 a in the counterclockwise directionof FIG. 33, the rollers 12 are wedged between the outer peripheralsurface of the inner ring 9 a and the inner peripheral surface of theouter ring 10 a, and rotation force is transmitted between the innerring 9 a and outer ring 10 a. On the other hand, when there is atendency for the outer ring 10 a to rotate at high speed in thecounterclockwise direction of FIG. 33 faster than the inner ring 9 a,the rollers 12 move against the elastic force of the springs 13 towardthe deep section of the concave sections 14, and the contact pressure atthe points of contact between the rolling contact surfaces of therollers 12 and the outer peripheral surface of the inner ring 9 a drops,and rotation force is not transmitted between the inner ring 9 a andouter ring 10 a (idling state).

In the case of the conventionally known roller clutches shown in FIGS.32 and 33 and described above, the cam surface 53 is located around theinner peripheral surface of the outer ring 10 a and the outer peripheraledge of the retainer 11 a fits with the concave sections 14 of this camsurface 53, so in the overrun state, the retainer 11 a rotates with theouter ring 10 a. Therefore, during operation, it is easy for thisretainer 11 a to rotate at high speed. However, in the case of thesecond and third examples of prior art construction described above,preventing the springs 13 from shifting in the outer radial directionwith respect to the protruding supports 57 a, 57 b formed on the columnsections 55 was not taken into consideration. Therefore, when the rollerclutch is in the overrun state and the retainer 11 a is rotating at highspeed, it becomes easy for the springs 13 to shift outward in the radialdirection with respect to the protruding supports 57 a, 57 b. Also, inthe extreme case, there is the possibility that the springs 13 will comeout from between the protruding supports 57 a, 57 b. In the case thatthe springs 13 shift or come out of place, it is not possible tomaintain the necessary performance of the roller clutch. Particularly,when this roller clutch is used in a rotation-transmission unit for theengine-starting apparatus of a so-called idling-stop vehicle, it is easyfor the problems described above to occur. The reasons why theseproblems easily occur will be explained below.

The function of an engine-starting apparatus of an idling-stop vehicleand the fact that it is necessary to use an apparatus with a built-inone-way clutch as the drive-pulley apparatus 6 (see FIG. 55) located onthe end of the rotation-drive shaft 5 of a starter motor 4 in order tohave this function are as explained above. Also, the possibility ofusing the prior known roller clutch shown in FIGS. 32 and 33 as thisdrive-pulley apparatus is as described above. Moreover, when using thiskind of roller clutch in the drive-pulley apparatus 6, it is possible todecrease vibration, noise and friction that occur when the clutch is notengaged, better than when a ratchet mechanism is used. Also, it ispossible to decrease the friction the occurs when the clutch is notengaged better than when a cam clutch, such as a sprag clutch is used.

Furthermore, in the case of the second and third examples of prior artconstruction of a roller clutch shown in FIGS. 32 and 33, together withforming a cam surface 53 around the inner peripheral surface of theouter ring 10 a, the retainer 11 a was made to rotate together with thisouter ring 10 a. Therefore, this differs from the case where the camsurface is formed around the outer peripheral surface of the inner ringand the retainer rotates together with the inner race, and the rollers12 are moved to the deep section of the concave sections 14 on the camsurface 53 by the centrifugal force that acts on the rollers 12 duringoperation. Therefore, in the overrun state, the rolling contact surfacesof the rollers 12 and the outer peripheral surface of the inner race 9 abecome separated, and it is possible to prevent rubbing between thesurfaces. As a result, it is possible to prevent the grease frombecoming degraded easily due to friction heat that occurs at the pointsof contact, and it is possible to prevent friction loss from becominglarge.

However, when using the examples of the roller clutch shown in FIGS. 32and 33 in the drive-pulley apparatus 6, after the engine starts, theretainer 11 a, the outer ring 10 a and the plurality of rollers 12continue to rotate at high speed. Therefore, a large centrifugal forceacts for a long time on the springs 13 that are supported by theprotruding support sections 57 a, 57 b of the retainer 11 a, and itbecomes easy for the springs 13 to shift toward the outer diameter sidewith respect to the protruding support sections 57 a, 57 b. Also, whenthe springs 13 shift a large amount toward the outer diameter side inthis way, it becomes impossible to maintain the necessary performance ofthe roller clutch. When the roller clutch shown in FIGS. 32 and 33 areused in the drive-pulley apparatus 6 in this way, it becomes easy forproblems to occur because the shifting of the springs 13 toward theouter diameter side with respect to the protruding support sections 57a, 57 b is not taken into consideration.

Moreover, when the roller clutch shown in FIGS. 32 and 33 is used in thedrive-pulley apparatus 6, in the locked state it transmits the torquefor starting the engine between the inner ring 9 a and outer ring 10 a,so the torque that must be transmitted between the inner ring 9 a andouter ring 10 a becomes large. Therefore, in order to change from theoverrun state to the locked state smoothly and completely, the elasticforce of the springs 13 must be larger than the elastic force of thesprings that are used in a normal roller clutch. However, when theelastic force of the springs 13 is large, the first and second problemsdescribed below occur. First, the first problem that occurs when theelastic force of the springs 13 is made large is that when the rollers12 and springs 13 are assembled in the retainer 11 a, the rollers 12 arepressed strongly to one section of the retainer 11 a. When the rollers12 are pressed like this, a part of the rollers 12 protrudes a lottoward the inner diameter side from the inner peripheral edge of theretainer 11 a, and there is a possibility that the diameter of theinscribed circle of the rolling contact surface of the plurality ofrollers 12 will become smaller than the outer diameter of the inner ring9 a. If the diameter of this inscribed circle is smaller than the outerdiameter of the inner ring 9 a, when the inner ring 9 a is pressedtoward the inner diameter side of the rollers 12 to assemble the rollerclutch 1, the end surfaces in the axial direction of the rollers 12interfere (collide) with the end surface in the axial direction of theinner ring 9 a. When these surfaces interfere with each other in thisway and the work of pressing the inner ring 9 a is continued, there is apossibility that the rollers 12 will fall from between the springs 13and column sections 55 inside the retainer 11 a. When the rollers 12fall out of place in this way, if the elastic force of the springs 13 issmall, it is easier to put the rollers 12 that fell out back into place.However, when the elastic force of the springs 13 in the roller clutchthat is used in an engine-starting apparatus is large, it is difficultto put the rollers 12 that fell out back into place, so the work ofassembling the roller clutch is troublesome.

As the second problem that occurs when the elastic force of the springs13 is too large is that when changing from the locked state to theoverrun state, the movement of the rollers 12 along the concave sections14 of the cam surface to the deep side of the concave sections 14 due tothe action of the centrifugal force may be hindered by the elastic forceof the springs 13. Particularly, in the third example of prior artconstruction shown in FIG. 33, in regards to the direction of movementof the center axis O of the rollers 12 when the rollers 12 move from thelocked state toward the overrun state along the concave sections 14 tothe deep side of the concave sections 14, when the springs 13 come incontact with the front ends of the rolling contact surfaces of therollers 12, it is easy for the movement of the rollers 12 along theconcave sections 14 toward the deep side of the concave sections 14 tobe hindered by the springs 13. Also, in regards to the direction of themovement of the center axis O from the locked state toward the overrunstate, when the springs 13 come in contact more with the rolling contactsurfaces of the rollers 12 on the outer diameter side of the retainer 11a than the position on the front ends of the rolling contact surfaces ofthe rollers 12, it becomes even easier for the movement of the rollers12 to be hindered. When the movement of the rollers 12 is hindered bythe springs 13 in this way, even in the overrun state the rollingcontact surfaces of the rollers 12 do not separate from the outerperipheral surface of the inner ring 9 a, and the rolling contactsurfaces of the rollers 12 rub against the outer peripheral surface ofthe inner ring 9 a, and thus it becomes easy for friction heat andfriction loss to occur at the points of contact between these surfaces.The occurrence of friction heat becomes the cause of a decrease in thedurability of the grease filled inside the roller clutch, and theoccurrence of friction loss becomes the cause of preventing animprovement in the performance of the mechanical apparatuses, such asthe automobile having an engine installed with a starting apparatus witha roller clutch.

The fourteenth to seventeenth examples of the invention shown in FIGS.25 to 31 take these problems into consideration, and they were inventedwith the object of eliminating at least the problems of the retainerrotating at high speed for a long time during operation, and the largeelastic force of the elastic members or springs that occur when used inthe engine-starting apparatus of an idling-stop vehicle.

First, FIGS. 25 to 27 show a fourteenth example of the invention. Thepulley apparatus 59 of this embodiment, which is a rotation-transmissionapparatus with built-in roller clutch for starting an engine, is used inthe engine-starting apparatus of the idling-stop vehicle shown in FIG.55 as the drive-pulley apparatus 6 for transmitting the rotation of therotation-drive shaft 5 of the starter motor 4 to the endless belt 7.Also, when electric power flows to the starter motor 4, it transmits therotation of the rotation-drive shaft 5 to the endless belt 7, howeverafter the engine 1 starts and the endless belt 7 is driven by the engine1, it does not transmit power from the endless belt 7 to therotation-drive shaft 5.

This pulley apparatus 59 comprises a pulley element 17 around whoseouter peripheral surface the endless belt 7 runs, and a sleeve 60 thatis fitted and fastened to the end of the rotation-drive shaft 5, suchthat it is concentric with the pulley element 17. The pulley element 17corresponds to the rotating member in the claims. Support bearings,which are a pair of ball bearings 19, and a roller clutch 61 are locatedbetween the outer peripheral surface of the sleeve 60 and the innerperipheral surface of the pulley element 17. Also, the inner peripheralsurface of the pulley element 17 and the outer peripheral surface of thesleeve 60 are simple cylindrical surfaces.

The roller clutch 61 is located in the middle in the axial direction ofthe circular-ring shaped space that exists between the outer peripheralsurface of the sleeve 60 and the inner peripheral surface of the pulleyelement 17, and the ball bearings 19 are located at both ends in theaxial direction of this circular-ring shaped space on both sides in theaxial direction of the roller clutch 61. Of these, the ball bearings 19are the same as those used in the first example shown in FIGS. 1 to 5and the outer races 24 of these ball bearings 19 are fitted and fastenedto the inner peripheral surface on both end portions of the pulleyelement 17 through interference fit, and the inner races 26 are fittedand fastened to the outer peripheral surface on both end portions of thesleeve 60 through interference fit. In the case of the example shown inthe figures, there is no pair of seal rings 28 a, 28 b (see FIG. 1) onthe ends in the axial direction of the ball bearings 19, however it ispossible to install seal rings 28 a, 28 b as in the first example.

Also, the roller clutch 61 transmits rotation force between the pulleyelement 17 and the sleeve 60 only when there is a tendency for relativerotation in a specified direction of the pulley 17 with respect to thesleeve 60. To construct this roller clutch 61, an inner member, orclutch inner ring 29, is fitted and fastened onto the middle section ofthe outer peripheral surface of the sleeve 60 through interference fit.This clutch inner ring 29 is formed into a generally cylindrical shapeby plastic working, such as pressing of steel plate such as carburizedsteel, and both of the inner and outer peripheral surfaces are simplecylindrical surfaces.

On the other hand, the outer member or clutch outer ring 30 is fittedand fastened into the middle section of the inner peripheral surface ofthe pulley element 17 through interference fit, and the inner peripheralsurface of the clutch outer ring 30 functions as a cam surface 31. Inother words, by forming a plurality of concave sections 14, called rampsections, on the inner peripheral surface of this clutch outer ring 30with an even space between them in the circumferential direction, suchthat the depth decreases gradually (gradually becomes shallow) going inone direction (left direction in FIG. 33), the inner peripheral surfaceof the clutch outer ring 30 functions as a cam surface 31. This outerclutch ring 30 is also formed into a generally cylindrical shape byplastic working, such as pressing of steel plate such as carburizedsteel.

Also, the roller clutch 61 comprises a plurality of rollers 33 togetherwith the clutch inner ring 29 and the clutch outer ring 30, and therollers 33 are supported by a clutch retainer 34 such that they can rollfreely and move a little in the circumferential direction. The clutchretainer 34 is fitted on the inside of the clutch outer ring 30 suchthat it cannot rotate with respect to the clutch outer ring 30. Thisclutch retainer 34 is made of synthetic resin (for example, a syntheticresin such as polyamide 66, polyamide 46, polyphenylene sulfide that ismixed 20% with glass fibers) and formed generally into a cage-typecylindrical shape, and comprises a pair of circular-ring shaped rimsections 35, and column sections 36 a that connect the rim sections 35to each other at a plurality of locations in the circumferentialdirection.

The sections surrounded on four sides by the inside surfaces of the rimsections 35 and the surfaces on the sides in the circumferentialdirection of the column sections 36 a form pockets 37 for holding therollers 33 such that they can roll freely and move a little in thecircumferential direction. A plurality of convex sections 56 that areformed at a plurality of locations on the outer peripheral surface ofthe rim sections 35 are fitted with the concave sections 14 formed onthe inner peripheral surface of the clutch outer ring 30, and the clutchretainer 34 is mounted to the clutch outer ring 30 such that it cannotrotate relative with respect to the clutch outer ring 30. Furthermore,inward facing collar sections 39 a, 39 b are formed on both ends in theaxial direction of the outer clutch ring 30, and by holding the clutchretainer 34 on both sides in the axial direction by the collar sections39 a, 39 b, the clutch retainer 34 does not move in the axial directionwith respect to the clutch outer ring 30.

Moreover, springs 13 are mounted on part of the column sections 36 a ofthis clutch retainer 34. In other words, in this example, as in thesecond and third examples of prior art construction shown in FIGS. 32and 33, these springs 13 are formed by bending spring steel plate intotriangular hook shapes. Also, protruding supports 57 a, 57 b are formedat three locations in the axial direction on the outside surfaces in theradial direction of the column sections 36 a of the clutch retainer 34such that they protrude toward the outside in the radial direction.Moreover, of these protruding supports 57 a, 57 b, the protrudingsupports 57 a are formed in a pair near both ends in the axial directionof the column section 36 a such that they both coincide with the phasein the circumferential direction of the clutch retainer 34. On the otherhand, one protruding support 57 b is formed in the middle section in theaxial direction of the column section 36 a and is out of phase in thecircumferential direction of the clutch retainer 34 with respect to theother protruding supports 57 a formed on the column section 36 a. Thebase sections 58 of the springs 13 are held between the pair ofprotruding supports 57 a formed near both ends in the axial direction ofthe column sections 36 a, and the protruding support 57 b that is formedin the middle section in the axial direction of the column sections 36a. With this construction, the base sections 58 of the springs 13 aresupported by part of the columns sections 36 a. Also, these springs 13elastically press the rollers 33 held in the pockets 37 in the samecircumferential direction of the clutch retainer 34 toward the sectionin the cylindrical space formed between the inner peripheral surface ofthe cam surface 31 and the outer peripheral surface (cylindricalsurface) of the clutch inner ring 29 where the width in the radialdirection becomes narrow.

Particularly, in this example, on the side surface in thecircumferential direction of the protruding support 57 b located in themiddle section in the axial direction of the column sections 36 a, aneave section 62 is located on the side surface that faces the sidesurface of the base section 58 of the springs 13 in the section that isseparated further on the outer-diameter side than the side surface ofthis base section 58, and it protrudes toward the side of this basesection 58. Also the length L₆₂ that the eave sections 62 protrude fromthe side surface in the circumferential direction of the protrudingsupports 57 b located in the middle section in the axial direction isgreater than the thickness t₁₃ of the base section 58 of the springs 13(L₆₂>t₁₃).

The function of the pulley apparatus 6 with built-in roller clutch 61constructed as described above when used in the engine-startingapparatus of a idling-stop vehicle is explained below. First, whenstarting the engine 1, electric power flows to the starter motor 4 andit turns the sleeve 60 that is fastened around the end of therotation-drive shaft 5 and the clutch inner ring 29 that is fastenedaround this sleeve 60 in a specified direction (counterclockwisedirection if FIG. 33). As this happens, the rollers 33 move toward thesection in the circular-ring shaped space formed between the outerperipheral surface of the clutch inner ring 29 and the inner peripheralsurface of the clutch outer ring 30 where the width in the radialdirection is narrow. As a result, the rolling contact surfaces of therollers 33 become wedged between the outer peripheral surface of theclutch inner ring 29 and the inner peripheral surface of the clutchouter ring 30, and the roller clutch 61 becomes locked, and rotation istransmitted from the clutch inner ring 29 to the clutch outer ring 30.In this state, the crankshaft 2 of the engine 1 (see FIG. 55) is drivenby way of the pulley element 17, endless belt 7 and follower pulley 3,and the engine 1 starts.

After the engine 1 has started, electric power stops flowing to thestarter motor 4 and the rotation-drive shaft 5 stops. In this state, thepulley element 17 is rotated and driven by the crankshaft 2 of theengine 1 by way of the endless belt 7 and the clutch outer ring 30continues to rotate in the specified direction. As a result, the rollerclutch 61 is set to the overrun state and does not transmit the rotationof the pulley element 17 to the sleeve 60. Therefore, when the engine 1is operating, the starter motor 4 does not become a load against therotation of the engine 1.

Particularly, in the case of the roller clutch assembled in therotation-transmission apparatus with built-in roller clutch for startingan engine of this embodiment, of the protruding supports 57 a, 57 bformed on the columns sections 36 a of the clutch retainer 34, eavesections 62 are located on the side surface in the circumferentialdirection of the protruding support 57 b located in the middle sectionin the axial direction and on the side that faces the side surface ofthe base section 58 of the springs 13, on the outer-diameter side of theside surface. Also the protruding length L₆₂ that the eave sections 62protrude from the side surface of the protruding support 57 b is greaterthan the thickness t₁₃ of the base sections 58 of the springs 13(L₆₂>t₁₃). Therefore, with this roller clutch, when a large centrifugalforce acts on the springs 13 due to the high-speed rotation of theclutch retainer 34 during operation, it is possible to prevent thesprings 13 from shifting or falling out of place toward theouter-diameter side with respect to the protruding supports 57 a, 57 b.Therefore, it is possible to improve the reliability of the rollerclutch.

As a result with the rotation-transmission apparatus with built-inroller clutch for starting the engine of an idling-stop vehicle in whichthis roller clutch is assembled, it is possible to prevent the springs13 from shifting toward the outer-diameter side and to improvereliability and durability of the roller clutch even though there is atendency for the springs 13 to shift outward due to the continuinghigh-speed rotation of the clutch retainer 34 with the clutch outer ring30 after the engine starts. Furthermore, in this example, the clutchretainer 34 is made of synthetic resin so it is lightweight and the workof manufacturing it can be simplified.

In this example, of the protruding supports 57 a, 57 b that are locatedon the column sections 36 a, eave sections 62 are formed on just theprotruding supports 57 b that are located in the middle section in theaxial direction for preventing the springs 13 from shifting outward orfalling out of place. However, it is also possible to form the same kindof eave sections on the side surfaces of the protruding supports 57 athat are located near both ends in the axial direction on the sidesurface and on the side that faces the side surface of the base section58. Also, it is possible to form eave sections on just the protrudingsupports 57 a that are located near both axial ends, without formingeave sections 62 on the protruding supports 57 b that are located in themiddle section in the axial direction. Increasing the number of eavesections 62 for each column section 36 a in this way is more effectivein preventing the springs 13 from shifting outward or falling out ofplace. However, in this case, the work of assembling the springs becomesvery troublesome when compared with this example. Also, the shape of thesprings 13 is not limited to a triangular hook shape as in this example,and a various shapes could be used, such as a ‘U’ shape. For example, inthe case of using a spring having a ‘U shape, one of the pair of armsections of the spring corresponds to the base section in claim 7.

Next, FIGS. 28 and 29 show a fifteenth example of the embodiment of theinvention. In this example, convex beveled sections 63, 64 (FIG. 29)that have a ¼ arc-shaped or partial conical-shaped cross section areformed on the outer edges of both ends in the axial direction of therollers 33 and of both end surfaces in the axial direction of the clutchinner ring 29. The total width in the radial direction of these bevelsections is regulated as explained below by the relationship between theroller 33 and the clutch inner ring 29.

In other words, as shown in FIG. 28, the state in which the rollers 33are held in the pockets 37 of the clutch retainer 34, and the rollingcontact surfaces of the rollers 33 are pressed to one end in thecircumferential direction of the pockets 37 (right ends in FIG. 28) bythe springs 13 in the clutch retainer 34 is considered. In this example,in this state, the rolling contact surfaces of the rollers 33 do notcome in contact with the cam surface 31 even when the clutch outer ring30 is located around this clutch retainer 34 such that the convexsections 56 fit with the concave sections 14 of the cam surface 31.Also, the state where the clutch retainer 34 and clutch inner ring 29are on the same axis, and the clutch inner ring 29 does not penetratethe inner-diameter side of the rollers 33, is considered. In the statewhere both members 34, 29 are placed in this way, the dimensions areregulated such that the amount δ that the rollers 33 move up toward theinner-diameter side more than the clutch track that is formed around theouter peripheral surface of the clutch inner ring 29 (the amount thatthe clutch inner ring 29 and the rollers 33 overlap in the axialdirection) is less than the total of the width W₁ in the radialdirection of the bevel section 63 on the ends of the rollers, and thewidth W₂ in the radial direction of the bevel sections 64 on the ends ofthe clutch inner ring 29 (δ<W₁+W₂). By satisfying this relationship,either one of the widths W₁, W₂ could be 0. In other words, it is alsopossible to form bevel sections on just the clutch inner ring 29 or therollers 33.

The work of assembling the roller clutch 61 a constructed as describedabove is performed as explained below. First, together with mounting thesprings 13 into the clutch retainer 34, the rollers 33 are held in thepockets 37 formed in the clutch retainer 34. In this state, the springs13 press the rollers 33 to one side in the circumferential direction ofthe pockets 37. Then the assembled rollers 33, springs 13 and clutchretainer 34 are installed on the inner-diameter side of the clutch outerring 30. When doing this, the convex fitting sections 56 formed on theclutch retainer 34 are fitted with the concave sections 14 formed on thecam surface 31 of the clutch outer ring 30, to prevent relative rotationbetween the clutch outer ring 30 and the clutch retainer 34. In theexample shown in the figures, on one end in the circumferentialdirection of the pockets 37, an inclined surface 65 having a V-shapedcross section is formed on both end sections in the axial direction ofthe surface of one side in the circumferential direction (right sidesurface is FIG. 28) of the column sections 55 a. Also, as describedabove, when the springs 13 press the rollers 33 to one side in thecircumferential direction of the pockets 37, the rolling contactsurfaces of the rollers 33 come in contact with the inclined surface 65.

Next, the clutch inner ring 29 is installed in the inner-diameter sideof the rollers 33. First, one end in the axial direction (right end inFIG. 29) of the clutch inner ring 29 is inserted on the inner-diameterside of (fitted into) the rollers 33. When performing this insertion,the bevel sections 63, 64 that are formed on the end sections in theaxial direction of the clutch inner ring 29 and the rollers 33 functionas guide surfaces.

At the instant when the work of inserting the clutch inner ring 29 inthe way begins, the phase in the circumferential direction of therollers 33 with respect to the clutch outer ring 30 is as shown by thesolid line in FIG. 28. In other words, the rollers 33 are located in thecomparatively shallow sections of the concave sections 14 of the camsurface 31 formed around the inner peripheral surface of clutch outerring 30. Also, in this state, a space s that is smaller than the amountδ that the rollers 33 protrude toward the inner-diameter side than thecylindrical surface around the outer peripheral surface of the clutchinner ring 29 exists in the space between the rolling contact surfacesof the rollers 33 and the concave sections 14. Also, in the sectionwhere the rollers 33 exist, the distance L between the outer peripheralsurface of the clutch inner ring 29 and the cam surface 31 formed aroundthe inner peripheral surface of the clutch outer ring 30 is less thanthe diameter D₃₃ of the rollers 33 (L<D₃₃). Therefore, with this phaseof the rollers 33 in the circumferential direction of the clutch outerring 30, it is difficult to fit the clutch inner ring 29 into theinner-diameter side of the rollers 33.

However, when installing the clutch inner ring 29 on the inner-diameterside of the rollers 33, cam surface 31 formed on the inner peripheralsurface of the clutch outer ring 30 moves the rollers 33 in thecircumferential direction against the elastic force of the springs 13.In other words, at the same time that the end in the axial direction ofthe clutch inner ring 29 enters the inner-diameter side of the rollers33 due to the fit between each of the bevel sections 63, 64, the outerperipheral surface of the clutch inner ring 29 presses the rollers 33against the inner peripheral surface of the clutch outer ring 30.Therefore, the rollers 33 receive a reaction force from the innerperipheral surface of the clutch outer ring 30 and the inclined surfacesof the concave sections 14 of the cam surface 31 formed around the innerperipheral surface of the clutch outer ring 30 presses the rollers 33 indirections orthogonal to the inclined surfaces. Also, of this force inthe orthogonal direction, the component force acting in thecircumferential direction of the clutch outer ring 30 moves the rollers33 against the elastic force of the springs 13, and as shown by thedashed line in FIG. 28, the rollers 33 move into a specified location inthe circumferential direction between the inner peripheral surface ofthe clutch outer ring 30 and the outer peripheral surface of the clutchinner ring 29, or in other words, the section where the space betweenthese two surfaces coincides with the diameter D₃₃ of the rollers 33. Inthis stat, the roller clutch 61 a is completely assembled.

Also, when assembling the pulley apparatus 59 (see FIG. 25) in whichthis assembled roller clutch 61 a has been installed, the clutch outerring 30 is tightly fitted into the pulley element 17 throughinterference fit (see FIG. 25), and the clutch inner ring 29 is tightlyfitted onto the sleeve 60 through interference fit (see FIG. 25). Inthis state, the roller clutch 61 a is assembled between the innerperipheral surface in the middle section of the pulley element 17 andthe outer peripheral surface in the middle section of the sleeve 60.

Moreover, a pair of ball bearings 19 (see FIG. 25) are installed betweenthe inner peripheral surface on both ends in the axial direction of thepulley element 17 and the outer peripheral surface on both ends in theaxial direction of the sleeve 60 so that they are located on both sidesin the axial direction of the roller clutch 61 a. In this state, thepulley apparatus 59 is completely assembled.

In the case of the rotation-transmission apparatus with built-in rollerclutch for starting the engine of an idling-stop vehicle of thisembodiment assembled as described above, bevel sections 63, 64 areformed on the outer peripheral edges of ends in the axial direction ofthe rollers 33 and ends in the axial direction of the clutch inner ring29. Also, in the state where the rollers 33 are held in the clutchretainer 34, and each of these rollers 33 is pressed by the springs 13located in the clutch retainer 34 toward part of the pockets 37, andwhere the clutch retainer 34 is placed concentric with the clutch innerring 29, the amount δ that the rollers 33 move further toward theinner-diameter side than the clutch track formed around the outerperipheral surface of the clutch inner ring 29 is less than the total ofthe width W₁ in the radial direction of the bevel sections 63 on theends of the rollers 33, and the width W₂ of the bevel sections 64 on theend of the clutch inner ring 29 (δ<W₁+W₂). Therefore, in this example,with the rollers 33 held in the clutch retainer 34, the work ofinserting the clutch inner ring 29 into the inner-diameter side of therollers 33 can be performed smoothly. Moreover, it is possible toprevent the rollers 33 from falling out of place into the inner-diameterside of the clutch retainer 34 due to interference between the ends inthe axial direction of the rollers 33 and the end in the axial directionof the clutch inner ring 29. Therefore, the work of assembling theroller clutch that is installed in the rotation-transmission apparatuswith built-in roller clutch for starting an engine of this embodimentcan be simplified. As a result, with the rotation-transmission apparatuswith built-in roller clutch for starting the engine of an idling-stopvehicle in which this roller clutch is installed, it is possible toprevent the rollers from falling out of place, and assembly work can beperformed easily even when the elastic force of the springs 13 is large.

The other construction and function are substantially the same as in thecase of the fourteenth example shown in FIGS. 25 to 27, so any redundantexplanation is omitted.

Next, FIG. 30 shows a sixteenth example of the embodiment of theinvention. In this example, of the opening sections of the pockets 37 ofthe clutch retainer 34, the width L₃₇ in the circumferential directionof the opening in the inner-diameter side of the clutch retainer 34 isless than the diameter D₃₃ of the rollers 33 (L₃₇ <D₃₃). In this kind ofexample, when the rollers 33 are held in pockets 37, the rollers 33cannot pass through the opening on the inner-diameter side. Therefore,when fitting the clutch inner ring 29 on the inner-diameter side of therollers 33 with the rollers 33 held in the clutch retainer 34 (see FIGS.25, 28 and 29), it is possible to prevent the rollers 33 from fallinginto the inner-diameter side of the clutch retainer 34 even when thereis interference with part of the rollers 33 and part of the clutch innerring 29. Therefore, in this example as well, similar to in the case ofthe fifteenth example described above using FIGS. 28 and 29, the work ofassembling the roller clutch 61 a can be performed easily. As a result,in the case of the rotation-transmission apparatus with built-in rollerclutch for starting the engine of an idling-stop vehicle in which thisroller clutch is installed, it is possible to perform assembly workeasily even when the elastic force of the springs 13 is large.

The other construction and functions are substantially the same as inthe case of the fifteenth example shown in FIGS. 28 and 29 describedabove, so any redundant explanation is omitted. The shape of the clutchretainer 34 is not limited to the shape shown in the figure, and variousshapes could be used as long as of the opening section of the pockets37, the width in the circumferential direction of the opening on theinner-diameter side of the clutch retainer 34 is less than diameter ofthe roller 33.

Next, FIG. 31 shows a seventeenth example of the embodiment of theinvention. In this example, the location where the rolling contactsurface of the rollers 33 of the roller clutch 61 b comes in contactwith the springs 13 is regulated by the relationship with the directionof movement of the rollers 33. In other words, the state in which therollers 33 are held between the cam surface 53 of the clutch outer ring30 and the outer peripheral surface of the clutch inner ring 29 andthese rollers 33 move along the concave sections 14 of the cam surface53 to the deep sides of the concave sections 14 is considered. Withrespect to the direction of movement (direction shown by the arrow X inFIG. 31) of the center axis O of the rollers 33 in this state, thedimensions of each section are regulated such that the tip edge of thesprings 13 comes in contact with the rolling contact surface of therollers 33 at a position (position indicated by the point Q in FIG. 31)further on the inside in the radial direction of the clutch retainer 34than the position (position indicated by the point P in FIG. 31) on thefront end of the rolling contact surface of the rollers 33. Also, inthis example, when the rollers 33 are held between the cam surface 53 onthe clutch outer ring 30 and the outer peripheral surface of the clutchinner ring 29, the direction that the springs 13 press the rollers 33coincides with the tangential direction in the circumferential directionof the clutch retainer 34.

With the construction of this example, the direction that the springs 13press the rollers 33 in the locked state (direction indicated by the Yarrow in FIG. 31) is inclined in the direction that a component force isproduced to press the rollers 33 in the concave section 14 with respectto the direction of movement (direction indicated by the arrow X in FIG.31) of the center axis O of the rollers 33 when the rollers 33 move fromthe locked state along the concave sections 14 to the deep side of theconcave sections 14. Therefore, in this example, when changing from thelocked state to the overrun state, the rollers 33 are moved easily alongthe concave sections 14 to the deep side of the concave sections 14 bythe centrifugal force even when the elastic force of the springs 13 usedin the engine-starting apparatus for an idling-stop vehicle is large.Therefore, in the overrun state, it is possible to prevent slidingcontact between the rolling contact surfaces of the rollers 33 and theouter peripheral surface of the clutch inner ring 29, and thus it ispossible to suppress the occurrence of friction heat and friction loss.Therefore, it is possible to improve the durability and performance ofthe roller clutch 61 b of this example. As a result, with therotation-transmission apparatus with built-in roller clutch for startingthe engine of an idling-stop vehicle in which this roller clutch 61 b isinstalled, it is possible to improve durability and performance evenwhen springs 13 having a large elastic force are used.

The other construction and function are substantially the same as in thefourteenth example shown in FIGS. 25 to 27 described above, so anyredundant explanation is omitted.

In each of the examples described above, the case in which the clutchouter ring 30 and clutch inner ring 29 of the roller clutch 61, 61 a, 61b are separate from the pulley element 17 and sleeve 60 (see FIG. 25,etc.), and fitted around the inner peripheral surface of the pulleyelement 17 and around the outer peripheral surface of the sleeve 60 wasexplained. However, in the fourteenth to seventeenth examples shown inFIGS. 25 to 31 described above, construction is not limited to this, andconstruction is possible in which the clutch outer ring is integratedinto one member with the pulley element, and the clutch inner ring isintegrated into one member with the sleeve. In this case, the pulleyelement becomes the outer member and the sleeve becomes the innermember.

Moreover, in the fourteenth to the seventeenth examples shown in FIGS.25 to 31 above, the case in which the roller clutch is assembled in apulley apparatus 59, which is a rotation-transmission apparatus withbuilt-in roller clutch for starting the engine of an idling-stop vehiclewas explained. In other words, the roller clutch described in thefourteenth to the seventeenth examples above is used in a startingapparatus that starts the engine of an idling-stop vehicle. However, theuse of the roller clutch assembled in the fourteenth to the seventeenthexamples above is not limited to this. For example, in otherrotation-transmission units for auxiliary drive apparatuses, where theretainer rotates at high speed for a long time during operation, andwhere there is a large torque transmitted between the clutch inner ring29 and clutch outer ring 30 in the locked state, use of the rollerclutch assembled in the fourteenth to the seventeenth examples above iseffective. For example, in an idling-stop vehicle, the roller clutch ofthe fourteenth to the seventeenth examples above can be assembledbetween the inner peripheral surface of the rotating member that rotatestogether with the rotating shaft of a compressor and the outerperipheral surface of a sleeve that rotates together with the rotatingshaft of the auxiliary drive motor when starting the compressor of aair-conditioning apparatus when the engine is stopped. A summary of theconstruction of the kind of roller clutch described in the fourteenth tothe seventeenth examples above (first to fifth roller clutches) and arotation-transmission unit for an auxiliary drive is given below.

First, similar to the second and third examples of a prior art rollerclutch shown in FIGS. 32 and 33, the first to the fifth roller clutcheseach comprise: an outer member; an inner member that is located on theinner-diameter side of the outer member; a cam surface that is locatedaround the inner peripheral surface of the outer member and that hasconcave sections at a plurality of locations in the circumferentialdirection and whose depth gradually decreases in one direction withrespect to the circumferential direction; a plurality of rollers thatare located in the cylindrical space between the inner peripheralsurface of the outer member and the outer peripheral surface of theinner member; a retainer that holds these rollers; and a plurality ofelastic members that have a base supported by part of the retainer,respectively, to press these rollers toward a section inside thecylindrical space where the thickness in the radial direction becomesnarrow. Particularly, the first roller clutch comprises a plurality ofprotruding supports that protrude in the radial direction and that areprovided on the outer peripheral surface in the middle section in theaxial direction of the retainer at a location to face the side surfaceof the base of the elastic members; and eave sections that are locatedon the side surfaces of the protruding supports, respectively, on theside to face the side surfaces of the bases of the elastic members andare located further toward the outer-diameter side than the sidesurfaces of the bases to protrude out from the base side of the elasticmembers. Also, the protruding length that these eaves protrude out fromthe side surface of the protruding supports is greater than thethickness of a section of the base of the elastic members that facesthis side surface.

Also, in the second roller clutch, bevel sections are formed on theouter peripheral edges of the end surfaces in the axial direction of therespective rollers, and/or the end surfaces in the axial direction ofthe inner member. When the rollers are held in pockets that are locatedat a plurality of locations in the circumferential direction of theretainer, respectively, such that the elastic force of the elasticmembers presses them toward part of the pocket, and when the innermember is located on the same axis line as the retainer at a locationseparated from the rollers in the axial direction, the amount that therollers move further toward the inner-diameter side than the clutchtrack formed around the outer peripheral surface of this inner member isless than the total of the width in the radial direction of the bevelsections on the end sections of the rollers and the width in the radialdirection of the bevel section on the end section of the inner member.

Moreover, in the third roller clutch, of the opening sections of theplurality of pockets located at a plurality of locations in thecircumferential direction of the retainer for holding the rollers, thewidth in the circumferential direction of the opening on theinner-diameter side is less than the diameter of the rollers.

Also, in the fourth roller clutch, when the rollers are held between thecam surface and the outer peripheral surface of the inner member andthese rollers move along the concave sections to the deep side of theconcave sections, the elastic members come in contact with the rollingcontact surface of the rollers at a location further on the inside inthe radial direction of the retainer than the front end of the rollingcontact surface of the rollers in the direction of movement of thecenter axis of the rollers.

Furthermore, the fifth roller clutch is the first to fourth rollerclutches in which the retainer is made of synthetic resin.

Also, the rotation-transmission unit for an auxiliary drive comprises; arotating member that rotates together with the rotating shaft of theengine or auxiliary device; a sleeve that rotates together with therotating shaft of the auxiliary device or auxiliary-drive motor such asa starter motor; and one of the aforementioned first to fifth rollerclutches that is located between the inner peripheral surface of therotating member and the outer peripheral surface of the sleeve.

With the first to fifth roller clutches and the rotation-transmissionunit for an auxiliary drive described above, it is possible to preventproblems that occur when the retainer rotates at high speed for a longtime during operation and when elastic members having a large springforce are used as in the case when assembled in an engine-startingapparatus for an idling-stop vehicle.

First, in the case of the first roller clutch, together with formingeave sections on the side surfaces of the protruding supports that facethe bases of the elastic members in a section that is located further onouter-diameter side than the bases, the protruding length that the eavesection protrude from the side surfaces of the protruding supports isgreater than the thickness of the portions of the bases that face theside surfaces. Therefore, even when a large centrifugal force acts onthe elastic members during operation due to the high-speed rotation ofthe retainer, it is possible to prevent the elastic members from comingout of place or shifting toward the outer-diameter side with respect tothe protruding supports, and thus it is possible to improve thereliability of the roller clutch. As a result, when therotation-transmission unit for an auxiliary drive in which this rollerclutch is assembled is used as an engine-starting apparatus for anidling-stop vehicle, even when the retainer continues to rotate at highspeed for a long time together with the outer member and there is atendency for the elastic member to easily shift toward theouter-diameter side, it is possible to prevent this shifting radiallytoward the outside and to improve reliability and durability.

Also, in the case of the second and third roller clutches, wheninserting the inner member into the inner-diameter side of the pluralityof rollers after the retainer and plurality of rollers have beenassembled, it is possible to prevent the rollers from falling into theinner-diameter side of the retainer due to interference between the endsurfaces in the axial direction of the rollers and the end surface inthe axial direction of the inner member. Therefore, the work ofassembling the roller clutch is simplified. As a result, when therotation-transmission unit for an auxiliary drive in which this rollerclutch is assembled is used as an engine-starting apparatus for anidling-stop vehicle, it is possible to prevent the rollers from fallingout even when elastic members having a large elastic force are used, andto simplify the work of assembly.

Moreover, in the case of the fourth roller clutch, when changing fromthe locked state to the overrun state even when the elastic force of theelastic members is large, the rollers move easily along the concavesection formed in the cam surface on the inner peripheral surface of theouter member to the deep side of the concave section due to thecentrifugal force. Therefore, in the overrun state, it is possible toprevent sliding contact from being kept between the rolling contactsurfaces of the rollers and the outer peripheral surface of the innermember, and to suppress the occurrence of friction heat and frictionloss. Therefore, it is possible to improve the durability andperformance of the roller clutch. As a result, when therotation-transmission unit for an auxiliary drive in which this rollerclutch is assembled is used as an engine-starting apparatus for anidling-stop vehicle, it is possible to improve the durability andperformance even when elastic members having a large elastic force areused.

Furthermore, the rotation-transmission apparatus for an auxiliary drivein which the fifth roller clutch is assembled makes it possible toreduce the weight as well as simplify manufacturing of the apparatus.

In this way, the rotation-transmission apparatus for an auxiliary drivein which the first to the fifth roller clutches are assembled make itpossible to prevent problems that occur when the retainer rotates athigh speed for a long time during operation, and when the elastic forceof the elastic members used is large.

Next, FIGS. 34 to 36 show an eighteenth example of the embodiment of theinvention, FIG. 37 shows a nineteenth example of the invention, FIG. 38shows a twentieth example of the invention, FIG. 39 shows a twenty firstexample of the invention, and FIG. 40 shows a twenty second example ofthe invention. Each of these examples was invented to maintainsufficient durability of a rotation-transmission apparatus with abuilt-in roller clutch for starting an engine, and more specificallywith the object of solving the following problems.

In other words, in recent years idling-stop vehicles as described aboveare in part actually being used. Moreover, in order to provide specifiedfunctions to the engine-starting apparatus of this kind of idling-stopvehicle, the use of an apparatus with a built-in one-way clutch, such asthe roller clutch 8 shown in FIG. 56 and described above, is consideredas the drive-pulley apparatus 6 (see FIG. 55) that is located on the endof the rotation-drive shaft of a starter motor 4. This roller clutch 8comprises a inner ring 9 and outer ring 10 that are arranged such thatthey are concentric with each other, and a retainer 11 and plurality ofrollers 12 and springs 13 that are located between the outer peripheralsurface of the inner ring 9 and the inner peripheral surface of theouter ring 10. Also, the outer peripheral surface of the inner ring 9 isa cam surface having a plurality of concave sections 14 called ramps,and the inner peripheral surface of the outer ring 10 is a simplecylindrical surface. Moreover, the springs 13 used for pressing therollers 12, can be plate springs 13 that are bent into a triangular hookshape as shown in FIG. 41, plate springs 13 a that are bent into anangular channel shape as shown in FIG. 42, or even plate springs 13 bthat are bent into and ‘S’ shape as shown in FIG. 43.

However, in the case of the roller clutch 8 described above, in theoverrun state where rotation force is not transmitted, or in otherwords, in the state where the springs 13, 13 a, 13 b are pressed by therollers 12, uneven wear and heat can occur due to partial slidingbetween the rollers 12 and the inner peripheral surface of the outerring 10 when the attitude of the rollers 12 shift from the normalposition in a direction that the center axis is tilted (skewed), andthis could lead to premature life of the rollers 12 or outer ring 10.Particularly, in the case when the roller clutch 8 that is assembled inan engine-starting apparatus for the idling-stop vehicle described aboveis used for a long time in the overrun state where rotation force is nottransmitted, preventing this kind of skew of the rollers 12 is importantfrom the aspect of maintaining durability (lengthening life). Even inthe locked state in which rotation force is transmitted, this kind ofskew of the rollers 12 could cause problems such as making it difficultfor the rollers 12 to fit properly between the outer peripheral surfaceof the inner ring 9 and the inner peripheral surface of the outer ring10, making it such that a specified amount of power cannot betransmitted between the inner ring 9 and outer ring 10, and making iteasy for large surface pressure to be applied causing damage as earlyflaking, and is not desirable.

In the case of the triangular hook shaped spring 13 shown in FIG. 41, inthe overrun state when the rotation force is not transmitted, or inother words, when the rollers 12 press by the springs, the space L inthe axial direction between the points of contact between the pair ofpressure sections 66 of these springs 13 and the rolling contactsurfaces of the rollers becomes small (short). When this space L betweenthe points of contact becomes small, the rigidity (moment rigidity) ofthe springs 13 that suppresses the moment load (force causing skew tooccur) applied to the rollers 12 drops, and due to unavoidable errors indimensions in these springs 13, it becomes easy for the direction thatthe springs 13 press the rollers 12 to shift from the proper direction.When the direction shifts, a moment is applied to the rollers 12 in adirection that tilts the rollers 12. As a result, it becomes easy forthe rollers 12 to become skewed. Also, when these rollers 12 are skewed,there is a possibility that the springs 13 will be unable to providesufficient pressure to restore the attitude of the rollers to the properposition. Therefore, there is a possibility that the problems describedabove may occur due to skew of the rollers 12 and lead to early life ofthe roller clutch.

Also, in the case of the springs 13 a bent into an angular channel shapeas shown in FIG. 42, in the overrun state in which the rotation force isnot transmitted, or in other words, the state in which the rollers 12press the springs 13 a, there is a possibility that large tensile stresswill be applied at the connecting areas between the main part 67 of thesprings 13 a and the pressure sections 66 a. When this kind of largetensile stress is applied to the connecting areas in this way, there isa possibility of plastic deformation of these connecting areas, and whenplastic deformation occurs, the proper amount of pressure is not appliedto the rollers 12. Also, due to the positional relationship between thepoints of contact α between the pressure sections 66 a of the springs 13a and the rolling contact surfaces of the rollers 12 and the center ofgravity G of the rollers 12, there is a possibility that a moment willbe applied to the rollers 12, which makes it easy for the rollers 12 tobecome skewed. Therefore, there is a possibility that the problemsdescribed above may occur due to skew of the rollers 12 and lead toearly life of the roller clutch.

Moreover, in the case of the springs 13 b that are bent into an ‘S’shape as shown in FIG. 43, there is normally linear contact between thesprings 13 b and the rollers 12, however, when these rollers 12 becomeeven a little skewed, the contact between the springs 13 b and rollers12 becomes point contact. Also, together with that, it is difficult forthe location of the contact between the springs 13 b and the rollers 12to be constant, and the locations of each of the contact points isalways changing. As a result, the direction that pressure is applied bythe springs 13 b becomes shifted from the direction of the center ofgravity of the rollers 12, and thus a moment is applied to the rollers12 and there is a possibility that tilt angle of the rollers 12 willbecome large. Therefore, there is a possibility that problems describedabove may occur due to skew of the rollers 12 and lead to early life ofthe roller clutch.

The eighteenth to twenty-second examples of the embodiment of theinvention shown in FIGS. 34 to 40 take the aforementioned problems intoconsideration, and by preventing skew of the rollers during the overrunstate (state when the rollers press the springs), provide arotation-transmission apparatus with built-in roller clutch for startingan engine having excellent durability (long life).

First, FIGS. 34 to 36 show an eighteenth example of the embodiment ofthe invention. The rotation-transmission apparatus with built-in rollerclutch for starting an engine of this embodiment is pulley apparatuswith built-in roller clutch, and the case of using it as thedrive-pulley apparatus 6 for transmitting the rotation of therotation-drive shaft 5 of the starter motor 4 to the endless belt 7 inthe engine-starting apparatus for the idling-stop vehicle shown in FIG.55 will be explained. The drive-pulley apparatus 6 assembled in thiskind of engine-starting apparatus transmits the rotation of therotation-drive shaft 5 to the endless belt 7 when electric power flowsto the starter motor 4, however, after the engine 1 starts and theendless belt 7 is driven by the engine 1, it does not transmit powerfrom the endless belt 7 to the rotation-drive shaft 5.

The pulley apparatus with built-in roller clutch that is used as thiskind of drive-pulley apparatus comprises a pulley element 17 (see FIG.25) around whose outer peripheral surface the endless belt 7 is placed,and a sleeve 60 (see FIG. 25) that is fitted and fixed onto the tip endof the rotation-drive shaft 5, that are located such that they areconcentric with each other. Also, as in the first example in FIGS. 1 to5, a pair of deep-groove type ball bearings 19 as support bearings, anda roller clutch 61 c are located between the outer peripheral surface ofthe sleeve 60 and the inner peripheral surface of the pulley element 17.In order to install these ball bearings 19 and roller clutch 61 c, theinner peripheral surface of the pulley element 17 and the outerperipheral surface of the sleeve 60 are simple cylindrical surfaces.However, in order to position the ball bearings 19 and roller clutch 61in the axial direction, a stepped section in the radial direction may beformed around the inner peripheral surface of the pulley element 17and/or outer peripheral surface of the sleeve 60. Also, the outer races24 (see FIG. 1) of the ball bearings 19 are fitted and fixed around theinner peripheral surface near both ends of the pulley element 17 throughinterference fit, and the inner races 26 (see FIG. 1) are fitted andfixed around the outer peripheral surface near both ends of the sleeve60 through interference fit. Differing from the case of the firstexample, the ball bearings 19 may be constructed without having a pairof seal rings 28 a, 28 b (see FIG. 1) on the ends in the axialdirection.

Moreover, the roller clutch 61 c transmits rotation force between thepulley element 17 and sleeve 60 only when there is a tendency for thepulley element 17 to rotate in a specified direction relative to thesleeve 60. To construct this kind of roller clutch 61 c, the clutchinner ring 29 is tightly fitted and fastened around the middle sectionof the outer peripheral surface of the sleeve 60. This clutch inner ring29 is made into a generally cylindrical shape by plastic working such aspressing of steel plate such as carburized steel, and the inner andouter peripheral surfaces are both simple cylindrical surfaces. Thesleeve 60 and clutch inner ring 29 could also be integrated into onemember.

On the other hand, the clutch outer ring 30 is tightly fitted andfastened around the inner peripheral surface in the middle of the pulleyelement 17, and the inner peripheral surface of the clutch outer ring 30is a cam surface 31. In other words, the inner peripheral surface ofthis clutch outer ring 30 is made into a cam surface 31 by forming aplurality of concave section 14, called ramp sections, on the innerperipheral surface such that they are evenly spaced in thecircumferential direction. This kind of clutch outer ring 30 is alsoformed into a generally cylindrical shape by plastic working such aspressing of steel plate such as carburized steel. The pulley element 17and the clutch outer ring 30 could also be integrated into a singlemember.

The rollers 33, which together with the clutch inner ring 29 and clutchouter ring 30 make up the roller clutch 61 c, are supported such thatthey can roll freely and move a little in the circumferential directionby a clutch retainer 34 that is fastened to the clutch outer ring 30such it cannot rotate with respect to the clutch outer ring 30. Thisclutch retainer 34 is made of synthetic resin (for example, a syntheticresin or plastic such as polyamide 66, polyamide 46, polyphenylenesulfide that is mixed 20% with glass fibers) and formed into a cage-typecylindrical shape, and comprises a pair of circular-ring shaped rimsections 35, and a plurality of column sections 36 a that connect therim sections 35 to each other.

The sections surrounded on four sides by the inside surfaces of the rimsections 35 and the circumferential side surfaces of the column sections36 form pockets 37 for holding the rollers 33 such that they can rollfreely and move a little in the circumferential direction. Also, convexsections 38 that are formed at a plurality of locations on the outerperipheral surface of the rim sections 35 are engaged with the concavesections 14 that are formed on the inner peripheral surface of theclutch outer ring 30 as shown in FIG. 35, so that the clutch retainer 34is mounted to the clutch outer ring 30 such that it does not rotaterelative to the clutch outer ring 30. Also, by holding the clutchretainer 34 on both sides in the axial direction by inward facing collarsections 39 a, 39 b that are formed on both end sections in the axialdirection of the clutch outer ring 30 (see FIG. 25), the clutch retainer34 does not move in the axial direction with respect to the clutch outerring 30.

Moreover, springs 68 are mounted as shown in FIGS. 34 to 36 on one sidesurface in the circumferential direction of the column sections 36 ofthe clutch retainer 34. The springs 68 located on the column sections 36elastically press the rollers 33 that are held in the pockets 37 in thesame circumferential direction (counterclockwise direction, or leftdirection in FIG. 35, upward in FIG. 36) of the clutch retainer 34 incylindrical space between the inner peripheral surface of the camsurface 31 and the outer peripheral surface (cylindrical surface) of theclutch inner ring 29 toward the section where the width in the radialdirection becomes narrow. In FIG. 34, in order to recognize easily theexistence of the springs, the springs 68 are drawn as compression coilssprings, however, actually, as shown in FIGS. 35 to 36, springs 68assembled are made bending plate steel such as stainless steel plate.This example differs from the fourteenth example shown in FIGS. 25 to27, in that there are no protruding eave sections 62 (see FIGS. 26 and27) that protrude from one side in the circumferential direction on partof the column sections 36 of the clutch retainer 34.

Particularly, the springs 68 of this example comprise a main section 69that comes in contact with the column section 36 of the clutch retainer34, and a pair pressure sections 70 whose base ends are continued toboth ends of the main section 69. Of these, the pressure sections 70 arecurved from the base ends to the tip ends, and when they are in contactwith the rolling contact surfaces of the rollers 33, they areindependently expand and contract. Also, as shown in FIG. 36( a) andFIG. 36( b), the location in the axial direction of the center ofgravity G of the rollers 33 is located between the points of contact α(furthest outside point) where the pressure sections 70 come in contactwith the rolling contact surface of the roller 33. Also, as shown inFIG. 36( b), when the pressure sections 70 are pressed by the rollers33, the length L₁ in the axial direction between the points of contact α(furthest outside point) where the pressure sections 70 come in contactwith the rolling contact surface of the rollers 33 is half or greaterthan the length L₂ in the axial direction of the rollers 33 (L₁≧(L₂/2)).

In the roller clutch 61 c constructed as described above, when there isa tendency for relative rotation in a specified direction of the pulleyelement 17 and sleeve 60, or in other words, when there is a tendencyfor the sleeve 60 to rotate relative to the pulley element 17 in thedirection that springs 68 are pressing the rollers 33 respectively (theleft direction or counterclockwise direction in FIG. 35), the rollers 33are wedged into the section in the substantially cylindrical spacebetween the outer peripheral surface of the clutch inner ring 29 and theinner peripheral surface of the clutch outer ring 30 where the width inthe radial direction becomes narrow. Also, relative rotation between thesleeve 60 and the pulley element 17 becomes impossible (locked state).On the other hand, when there is a tendency for relative rotation of thepulley element 17 and the sleeve 60 in the direction opposite to thespecified direction, or in other words when there is a tendency forrelative rotation in the direction opposite to the direction the springs68 are pressing the rollers 33 (right direction or clockwise directionin FIG. 35), the rollers 33 move back against the elastic force of thesprings 68 into the section in the substantially cylindrical space wherethe width in the radial direction is wide, and the pulley 17 freelyrotates relative to the sleeve 60 (overrun state).

With the rotation-transmission apparatus with built-in roller clutch forstarting an engine of this example assembled with the roller clutch 61 cconstructed as described above, in the overrun state, or when therollers 33 press the springs 68, it is possible to prevent the attitudeof the rollers 33 from shifting in a direction such that the center axistilts (becomes skewed). Therefore, it is possible to prevent uneven wearor abnormal heat due to the skew of the rollers 33, and thus it possibleto improve the durability (long life) of the roller clutch 61 c and therotation-transmission apparatus with built-in roller clutch for startingan engine that is assembled with this roller clutch 61 c.

In other words, in this embodiment, the springs 68 that press therollers 33 come in contact with the rollers at two points separated inthe axial direction by the pair of pressure sections 70 of these springs68 respectively. Therefore, even when the location of the contactbetween the pressure sections 70 and the rollers 33 changes a little, itis possible to prevent large changes in the force or moment applied tothe rollers 33, and thus it is possible to keep the attitude of therollers 33 in the proper position. In other words, in the case of the‘S’ shaped spring 13 b shown in FIG. 43, the springs 13 b and therollers 12 come in contact at one point (linear contact) respectively,however it is rare that the springs 13 b and the rollers 12 will come inproper linear contact, and when the rollers 12 become even a littleskewed, the contact state changes from linear contact to point contact.Therefore, the pressure force of the springs 13 b is shift in thedirection of the center of gravity of the rollers 12, and it becomeseasy for a moment to be applied to the rollers 12, and it becomes easyfor the inclination of the rollers 12 to increase. On the other hand, inthe case of this example, as described above, the rollers 33 and thesprings 68 come in contact with each other at two points separated inthe axial direction by the pair of pressure sections 70 of the springs68, so it is possible to keep the attitude of the rollers 33 at a properposition.

Also, since springs 68 and rollers 33 come in contact with each other attwo points by the pair of pressure sections 70 of the springs 68, it ispossible for these pressure sections 70 to independently expand andcontract. Therefore, in the case that the rollers 33 become skewed, alarge reaction force occurs in the pressure section 70 in which theamount of displacement (amount of expansion or contraction) is large. Asa result, a moment is applied to the rollers 33 that returns the rollers33 to the proper position, and thus it is possible to keep the positionof the rollers 33 at the proper position. Also, since the location inthe axial direction of the center of gravity G of the rollers 33 islocated between the points of contact α (furthest outside) between thepressure sections 70 and the rollers 33 respectively, it is possible toprevent the relationship between the center of gravity G of the rollersand the direction of pressure of the pressure sections 70 from becomingimproper. As a result, it is possible to prevent a moment from beingapplied to the rollers 33, and it is possible to prevent the rollers 33from becoming skewed.

Moreover, when the pressure sections 70 are pressed by the rollers 33,the space L₁ in the axial direction between the points of contact α(furthest outside) between the pressure sections 70 and the rollers 33is half or greater than the length L₂ in the axial direction of therollers 33 (L₁≧L₂/2), so no matter how the attitude of the roller 33changes, or no matter how the pressure sections 70 are pressed by therollers 33, the center of gravity G of the rollers 33 is always locatedbetween the points of contact α. Therefore, since the rollers 33 come incontact with the springs 28 at two points, it is possible to maintainsufficient stabilizing action on the attitude of rollers 33, and thus itis possible to keep the attitude of the rollers 33 proper.

Furthermore, since the pressure sections 70 are curved from the base endto the tip end, in either the case where the pressure sections 70 faceinward as in this example (the pair of pressure sections 70 are curvedin a direction toward each other), or the case where the pressuresections 70 a face outward as in the nineteenth example of the inventionshown in FIG. 37 (the pair of pressure sections 70 a are curved in adirection away from each other), it is possible to maintain sufficientpressure force of the pressure sections 70, 70 a.

In other words, when the pressure sections 70 face inward as in thisexample, even when the pressure sections 70 are deformed by beingpressed by the rollers 33, it is difficult for the space L₁ in the axialdirection between the points of contact α between the pressure sections70 and rollers 33 to become smaller. Also, when the pressure sections 70elastically deform, the points of contact α between the pressuresections 70 and rollers 33 move toward the side of base end of thepressure sections 70, so the apparent length of the pressure sections 70becomes shorter, and the spring constant becomes greater. Therefore, thepressure force of the pressure sections 70 becomes greater and thus theforce for restoring the tilt of the rollers 33 is increased.

On the other hand, when the pressure sections 70 a face outward as inthe nineteenth example of the invention shown in FIG. 37, it is possibleto reduce the tensile stress that is applied at the area where thepressure sections 70 a connect with the main section 69, and thus it ispossible to prevent a loss in pressure force due to plastic deformationat these connecting areas. In other words, when the pressure sections 70a are pressed by the rollers 33 there is a tendency for elasticdeformation to occur in not only the connecting areas but in the curvedsections of the pressure sections 70 a as well. Therefore, as a resultof being able to also apply a pressure force to the rollers 33 by thecurved section of the pressure sections 70 a, it is possible to reducethe accumulation of tensile stress at the connecting areas. Also, whenthe pressure sections 70 a elastically deform, the locations of contactbetween the pressure sections 70 a and the rollers 33 move toward theside of base end of the pressure sections 70 a, so the apparent lengthof the pressure sections 70 becomes shorter, and thus the springconstant becomes larger. Therefore, as in the case when the pressuresections 70 face inward as shown in FIG. 36, the pressure force of thepressure sections 70 a becomes larger, and thus the force for restoringthe tilt of the rollers 33 is increased.

In the case where the rotation-transmission apparatus with built-inroller clutch for starting an engine of the eighteenth and nineteenthexamples constructed as described above and assembled with the rollerclutch 61 c described above is used as the drive-pulley apparatus 6 ofthe engine-starting apparatus for the idling-stop vehicle shown in FIG.55, when the roller clutch 61 c is in the overrun state, the rollers 33are pressed by the column sections 36 of the clutch retainer 34 and thesprings 68 to rotate together with the clutch outer ring 30 fastened onthe inside of the pulley element 17 (see FIG. 25). However, when the rpmof this clutch outer ring 30 is less than the rpm required for startingthe engine 1 (see FIG. 55) (speed after the gear ratio of the belttransmission mechanism is multiplied to 400 rpm to 500 rpm, for examplein the case of a gasoline engine), the centrifugal force that acts onthe rollers 33 is not enough to compress the springs 68. Also, whenstarting the engine 1, a force is applied to the rollers 33 from theouter peripheral surface of the clutch inner ring 29 in the samedirection as the elastic force of the springs 68. Therefore, whenstarting the engine 1, the rollers 33 move in the space between theouter peripheral surface of the clutch inner ring 29 and the innerperipheral surface of the clutch outer ring 30 toward the section wherethe width becomes narrow, and the roller clutch 61 is securely set intothe locked state.

On the other hand, when the engine 1 starts and the rpm of the clutchouter ring 30 becomes greater than the rpm for idling of the engine 1(speed after the gear ratio of the belt transmission mechanism ismultiplied to 700 rpm to 800 rpm, for example in the case of a gasolineengine), not only is the connection of the roller clutch 61 c broken(the overrun state is set), but the rolling contact surfaces of therollers 33 of the roller clutch 61 c become separated from the outerperipheral surface of the clutch inner ring 29.

In other words, when the engine 1 is rotating, a centrifugal force actson the rollers 33, and the rollers 33 are pushed against the bottomsurface of the concave sections 14. The bottom surface of the concavesections 14 is inclined, so the rollers 33 have a tendency to move inthe direction to press the springs 68 (to compress the springs 68).Also, after the engine 1 has started, electric power stops flowing tothe starter motor 4 and the clutch inner ring 29 stops, so that theforce trying to move the rollers 33 in the counterclockwise direction ofFIGS. 34 and 35 is just the elastic force of the springs 68.

In this state, the centrifugal force increases as the rotation forceincreases, and when the size of this component force becomes larger thanthe elastic force of the springs 68, the rollers 33 compress the springs68 and move toward the deep section of the concave sections 32. As aresult, as described above, the rolling contact surfaces of the rollers33 separate from the outer peripheral surface of the clutch inner ring29. As described above, when the springs 68 are compressed by therollers 33, it is possible to prevent the rollers 33 from becomingskewed, so it is possible to prevent increase in friction loss, unevenwear and abnormal heat due to this kind of skewing, and thus it ispossible to improve the durability (long life) of therotation-transmission apparatus with built-in roller clutch for startingan engine. Particularly, in the overrun state described above, the forceapplied to the rollers 33 is the pressure force of the springs 68 andthe centrifugal force that resists is pressure force, and furthermore,the friction force from the outer peripheral surface of the clutch innerring 29 when rotating a low speed, however, in the eighteenth andnineteenth examples, the skew of the rollers 33 is prevented regardlessof the uneven friction force received from the outer peripheral surfaceof the roller clutch inner ring 29 and the unavoidable dimension errorswhen manufacturing the springs 68, so it is possible to prevent problemsdue to the skew.

The other construction and function are substantially the same as in thefourteenth examples shown in FIGS. 25 to 27.

Next, FIG. 38 shows a twentieth example of the embodiment of theinvention. In this example, the area where the main section 69 and pairof pressure sections 70 of the springs 68 connect is smooth. In thisexample, when the pressure sections 70 are pressed by the rollers 33 tobe elastically deformed, both ends of the area of contact between themain section 69 and column section 36 of the clutch retainer 34 (seeFIGS. 34 and 35) move toward the tip end side of the pressure sections70. Therefore, the location of the points of contact between thepressure sections 70 and the rollers 33 move toward the based end sideof the pressure sections 70 and the apparent length of the pressuresections 70 becomes short, and thus it is possible to increase the forcefor restoring the tilt of the rollers 33. The other construction andfunction are substantially the same as in the eighteenth example shownin FIGS. 34 to 36.

Next, FIG. 39 shows a twenty-first example of the embodiment of theinvention. In this example, the pair of pressure sections 70 b of thesprings 68 are curved such that the radius of curvature of the curvefrom the base end section to the tip end section of the pressuresections 70 b gradually decreases (the radius of curvature graduallybecomes smaller). In other words, the pressure sections 70 are such thatthe amount of curvature becomes large toward the tip end side. In thisexample, it is possible to reduce the stress applied to the base endside of the pressure sections 70 b, and to maintain the necessarypressure force without having to increase the size of the springs 68 b.In other words, the stress applied to the pressure sections 70 bincreases near the base end side and becomes larger the smaller theradius of curvature (larger amount of curvature). On the other hand, inthis example, by making the radius of curvature at the base end side ofthe pressure sections 70 b large (small amount of curvature), the stressapplied at the base end side is small. Also, by making the radius ofcurvature at the tip end side of the pressure sections 70 b small (largeamount of curvature), the pressure force of these pressure sections 70 bis maintained. The other construction and function are the same as inthe eighteenth example shown in FIGS. 34 to 36.

Next, FIG. 40 shows a twenty-second example of the embodiment of theinvention. In this example, the main section 69 and pair of pressuresections 70 b of the springs 68 c are connected by a smooth curve, andthe radius of curvature of the curve from the base end to the tip end ofthe pressure sections 70 b gradually decreases (amount of curvaturegradually increases). In this example, by regulating the space L₃₃ inthe axial direction between the locations of contact between thepressure sections 70 b and the rollers 33 and the space L₃₆ of the areaof contact between the main section 69 and the column section 36 of theclutch retainer 34 (see FIGS. 34 and 35), it is possible to easilyobtain the desired spring characteristics. The other construction andfunction are substantially the same as in the twentieth example shown inFIG. 38 and the twenty-first example shown in FIG. 39.

In the eighteenth to twenty-second examples shown in FIGS. 34 to 40 anddescribed above, the case in which the rotation-transmission apparatuswith built-in roller clutch was assembled and used in theengine-starting apparatus for an idling-stop vehicle was explained.However, the use of the rotation-transmission apparatus with built-inroller clutch of the eighteenth to twenty-second examples is not limitedto the engine-starting apparatus. Using the rotation-transmissionapparatus with built-in roller clutch of the eighteenth to twenty-secondexamples is effective in applications where the rpm of the rotatingmember during the overrun state is greater than the rpm of the rotatingmember in the locked state, and where the operating time in the overruntime is a long time. As an example of this kind of use is theauxiliary-drive apparatus such as a compressor assembled in anidling-stop vehicle. Also, the operating time in the overrun state isnot long, however, use as the drive-pulley apparatus, and the one-wayclutch of this drive-pulley apparatus, assembled in the driveapparatuses of auxiliary devices such as an alternator or water pump ispossible.

Each of the roller clutches described in the eighteenth to twenty-secondexample above have two concentric members and were used in the casewhere one of the member rotates in either direction and where rotationis transmitted to the other member only in one direction. Also, thepulley apparatus with built-in roller clutch of the eighteenth totwenty-second examples assembled with the roller clutch described above,can also be used for transmitting the rotation of the engine crankshaftin an auxiliary devices such as an alternator for various kind ofengines. The construction of the roller clutch and pulley apparatus withbuilt-in roller clutch of the eighteenth to twenty-second example issummarized as follows.

First, the roller clutch of the eighteenth to twenty-second examplescomprises: a outer ring-like member, inner ring-like member, camsurface, cylindrical surface, a plurality of rollers, retainer andsprings.

Of these, the inner ring-like member is located on the inside of theouter ring-like member such that it is concentric with the outerring-like member.

The cam surface is uneven around in the circumferential direction and isformed on either the inner peripheral surface of the outer ring-likemember or the outer peripheral surface of the inner ring-like member.

The cylindrical surface is formed on the other surface; the innerperipheral surface of the outer ring-like member or outer peripheralsurface of the inner ring-like member.

The rollers are located in the cylindrical space between the cylindricalsurface and the cam surface.

The retainer is supported inside the cylindrical space such that itcannot rotate with respect to the member on which the cam surface isformed, and it holds the plurality of rollers.

The springs are made of metal, are located between the retainer and therollers, and press the rollers in the same circumferential direction.

Particularly, in the roller clutch of the eighteenth to twenty-secondexamples above, the springs comprise a main section that comes incontact with part of the retainer, and a pair of pressure sections whosebase ends are connected to both ends of the main section. Of these, thepressure sections are curved from the base end to the tip end, and whenthey come in contact with the rolling contact surfaces of the rollers,they expand and compress independently. Also, the location in the axialdirection of the center of gravity of the rollers is located between thepoints of contact between the pressure sections and the rolling contactsurface of the roller. Also, together with this, when the pressuresections are pressed by the rollers, the space in the axial directionbetween the points of contact between the pressure sections and therolling contact surface of the roller is half or greater than the lengthin axial direction of the rollers.

Also, the pulley apparatus with built-in roller clutch of the eighteenthto twenty-second examples above comprises a sleeve, pulley, radialrolling bearings, and roller clutch.

Of these, the sleeve is fitted and fastened onto the rotating shaft.

Also, the pulley has a cylindrical shaped inner peripheral surface, andit is located around the sleeve such that it is concentric with thesleeve.

The radial rolling bearings are located between the outer peripheralsurface of the sleeve and the inner peripheral surface of the pulley,and they support radial loads that are applied to the pulley, and allowthe sleeve to rotate freely with respect to the pulley.

Furthermore, the roller clutch is for the sixth roller clutch mentionedabove, and it is located between the outer peripheral surface of thesleeve and the inner peripheral surface of the pulley in the sectionseparated in the axial directed from the radial rolling bearings.

With the roller clutch and pulley apparatus with built-in roller clutchof the eighteenth to twenty-second examples constructed as describedabove, in the overrun state, or in other words, when the springs arepressed by the rollers, it is possible to prevent the attitude of therollers from shifting (skewing) in the direction that the center axis istilted from the proper position. Therefore, it is possible to preventuneven wear and abnormal heat due to the skewing of the rollers, andthus it is possible to improve the durability (long life) of the rollerclutch and pulley-apparatus with built-in roller clutch. Therefore, itis possible to improve the performance of various mechanicalapparatuses, such as improving the reliability and durability of theengine-starting apparatus for an idling-stop vehicle.

Next, FIGS. 44 and 45 show a twenty-third example of the embodiment ofthe invention, FIG. 46 shows a twenty-fourth example, FIG. 47 shows atwenty-fifth example and FIG. 48 shows a twenty-sixth example. Theexamples as well were invented in order to sufficiently maintain thedurability of a rotation-transmission apparatus with built-in rollerclutch for starting an engine, and specifically with the object ofsolving the following problems.

In other words, in recent years, idling-stop vehicles as described aboveare actually being used. In order to give the engine-starting apparatusfor this kind of idling-stop vehicle certain function, using anapparatus with a built-in one-way clutch in which the roller clutch 8shown in FIG. 56 and described above is assembled as the drive-pulleyapparatus (see FIG. 55) that is located on the end of the rotation-driveshaft of the starter motor 4 is considered. However, as described above,in the case of the roller clutch 8 shown in FIG. 56, rubbing at thepoints of contact between the rolling contact surfaces of the rollers 12and the inner peripheral surface of the outer ring 10 is unavoidableeven when rotation force is not being transmitted between the inner ring9 and outer ring 10. Therefore, when the overrun state continues for along time, the amount of friction heat that is generated at these pointsof contact cannot be ignored and it causes the temperature inside theroller clutch 8 to rise, and thus it becomes easy for the grease filledinside the roller clutch 8 to become degraded. Furthermore, thetemperature in the support bearings next to the roller clutch 8 rises,and this makes it easy for the rubber or synthetic resin seal platesassembled in these support bearings to degrade. In the case of a pulleyapparatus with a built-in one-way clutch for an alternator, operation isbasically in the locked position, as will be described below, and sinceoperation in the overrun state is for a short time, the friction heatand rise in temperature described above does not easily become aproblem.

However, in the case of the one-way clutch that is assembled in thedrive-pulley apparatus 6 for the idling-stop vehicle shown in FIG. 55and described above, the locked state occurs only for a short time whenstarting the engine, and after the engine starts, operation is in theoverrun state as long as the engine is operating. Therefore, it isdifficult to maintain sufficient durability even when the roller clutch8 as shown in FIG. 56 is assembled in the engine-starting apparatus foran idling-stop vehicle.

Taking this problem into consideration, the inventors invented a pulleyapparatus with built-in roller clutch as shown in FIGS. 49 to 51(Japanese Patent Application No. 2002-33835). The pulley apparatus 16with built-in roller clutch of this prior invention comprises a pulleyelement 17 around whose outer peripheral surface an endless belt 7 (seeFIG. 55) runs, and a sleeve 18 fitted and fastened onto the tip end ofthe rotation-drive shaft 5 (see FIG. 55), which are arranged such thatthey are concentric with each other. Also, a pair of deep-groove ballbearings 19 as support bearings and a roller clutch 20 are locatedbetween the outer peripheral surface of the sleeve 18 and the innerperipheral surface of the pulley element 17. In order to install theball bearings 19 and the roller clutch 20, the inner peripheral surfaceof the pulley element 17 is a simple cylindrical surface, and the outerperipheral surface of the sleeve 18 is a stepped cylindrical surfacehaving a large-diameter section 21 in the middle section in the axialdirection and small-diameter sections 22 on both ends that are connectedat the step sections.

The roller clutch 20 is located in the circular space that existsbetween the outer peripheral surface of the sleeve 18 and the innerperipheral surface of the pulley element 17, and similarly, the ballbearings 19 are located in this circular space near both ends in theaxial direction such that they are on both side in the axial directionof the roller clutch 20. Of these, the ball bearings 19 are placed suchthat they are concentric with pulley element 17 and sleeve 18, and theyserve the role of allowing both of these members 17, 18 to freely rotaterelative to each other. In the example shown in the figures, by placingthe ball bearings 19 on both sides of the roller clutch 20, the span forapplication of the radial loading is lengthened, so that it is possibleto increase the rigidity as well as maintain durability. Also, byapplying contact angles that face away from each other (preferably aback-to-back combination type), they freely support axial loads that areapplied to the pulley element 17 in both directions.

The ball bearings 19 comprise: an outer race 24 having an outer racetrack 23 of the deep-groove type formed around the inner peripheralsurface thereof; an inner race 26 having an inner race track 25 of thedeep-groove type formed around the outer peripheral surface thereof, anda plurality of balls 27 that are located between the outer race track 23and inner race track 25 such that they can roll freely. The outer races24 are tightly fitted and fastened around the inner peripheral surfacenear both ends of the pulley element 17, and the inner race 26 aretightly fitted and fastened around the outer peripheral surface of thesmall-diameter sections 22 on both ends of the sleeve 18 throughinterference fit, respectively. Moreover, in this state, one surface inthe axial direction of the respective inner races 26 comes in contactwith the surface of the step sections where the large-diameter section21 connects with the small-diameter sections 22.

Also, by placing seal rings 28 a, 28 b between the inner peripheralsurface on both ends of the outer races 24 and the outer peripheralsurface on both ends of the inner races 26, the openings on both ends tothe spaces where the balls 27 are located are covered. Moreover,lubricant such as grease is filled inside this space, to lubricate thepoints of contact between the outer race track 23 and the inner racetrack 25 and the rolling contact surfaces of the balls 27.

Furthermore, only when there is a tendency for the pulley element 17 torotate relative to the sleeve 18 in a specified direction, the rollerclutch 20 transmits rotation force between the pulley element 17 and thesleeve 18. In order to construct this roller clutch 20, the clutch innerring 29 is tightly fitted and fastened around the large-diameter section21 of the sleeve 18 through interference fit. This clutch inner ring 29is formed generally into a cylindrical shape by plastic working such aspressing of steel plate such as carburized steel, such that the innerperipheral surface and outer peripheral surface are both simplecylindrical surfaces.

On the other hand, the inner peripheral surface of the clutch outer ring30 that is tightly fitted and fastened around the inner peripheralsurface of the middle section of the pulley element 17 is a cam surface31. In other words, as shown in FIGS. 50 and 51, a plurality of concavesections 32, called ramp sections are formed, around the innerperipheral surface of the clutch outer ring 30 such that they are evenlyspaced around in the circumferential direction whereby the cam surface31 is formed. This clutch outer ring 30 is also formed generally into acylindrical shape by plastic working such as pressing of steel platesuch as carburized steel.

Also, the plurality of rollers 33 that together with the clutch innerring 29 and clutch outer ring 30 make up the roller clutch 20, are heldsuch that they can freely roll and move a little in the circumferentialdirection by a clutch retainer 34 that is fastened to the clutch outerring 30 such that it cannot rotate with respect to the clutch outer ring30. This clutch outer ring 34 is formed into a generally cage-typecylindrical shape from a synthetic resin (for example, a synthetic resinor plastic like polyamide 66, polyamide 46 or polyphenylene sulfide thatis mixed with about 20% glass fiber), and comprises a pair of circularring shaped rim sections 35, and a plurality of a column sections 36that connect these rim sections 35 together.

Also, the sections surrounded on four sides by the inside surfaces ofthe rim sections 35, 35 and the side surfaces in the circumferentialdirection of the columns sections 36, form pockets 37 for holding therollers 33 such that they can rotate freely as well as move freely alittle in the circumferential direction. Moreover, as shown in FIG. 51,convex section 38 are formed at a plurality of locations around theouter peripheral surface of the rim sections 35 such that they fit withthe concave section 32 formed on the inner peripheral surface of theclutch outer ring 30, such that the clutch retainer 34 is mounted to theclutch outer ring 30 such that it cannot rotate relative to the clutchouter ring 30. Also, by holding the clutch retainer 34 on both sides inthe axial direction by collar sections 39 a, 39 b that are formed onboth end sections in the axial direction of the clutch outer ring 30,this clutch retainer 34 is not able to move in the axial direction withrespect to the clutch outer ring 30.

Furthermore, springs 40 are mounted as shown in FIGS. 50 and 51 on oneof the side surfaces in the circumferential direction of the columnsections 36 of the clutch retainer 34. These springs 40 that are locatedon each column section 36 elastically press the rollers 33 that held inthe pockets 37 in the same direction (counterclockwise direction inFIGS. 50 and 51) in the circumferential direction of the clutch retainer34 in cylindrical space formed between the inner peripheral surface ofthe cam surface 31 and the outer peripheral surface (cylindricalsurface) of the clutch inner ring 29 toward the section where the widthin the radial direction becomes narrow.

In FIGS. 50 and 51, the springs 40 are drawn as compression coilsprings, however, actually plate springs that are made by bending springsteel into a triangular-shaped hook are often used for these springs 40.In other words, as shown in FIGS. 52 to 54, the base section 72 of thespring 40 is supported by protruding supports 71 a, 71 b that are formedon the outer peripheral surface of the column sections 36, 36 of theclutch retainer 34, and the pair of elastic members 73, 73 formed ineach spring 40 press the rollers 33 in the same circumferentialdirection. Furthermore, it is also possible to use synthetic resinsprings that are made in one piece with the clutch retainer 34. Thiskind of roller clutch 20 is lubricated by grease that is filled insideit.

In the roller clutch 20 constructed as described above, when there is atendency for relative rotation of the pulley element 17 and sleeve 18 ina specified direction, or in other words, when there is a tendency forthe sleeve 18 to rotate relative to the pulley element 17 in thedirection that the springs 40 press the rollers 33 (counterclockwisedirection in FIGS. 50 and 51), the rollers 33 are wedged into thesection of the cylindrical space where the width in the radial directionis narrow. In this state the relative rotation of the sleeve 18 andpulley element 17 is not possible (locked state). On the other hand,when there is a tendency for relative rotation of the pulley element 17and sleeve 18 in the direction opposite to the specified direction, orin other words, in the direction opposite to the direction that thesprings 40 press the rollers 33 (clockwise direction in FIGS. 50 and51), the rollers 33 move against the elastic force of the springs backinto the section in the cylindrical space where the width in the radialdirection is wide, and the pulley element 17 rotates freely relative tothe sleeve 18 (overrun state).

The function when the pulley-apparatus 16 with built-in roller clutch ofthis invention constructed as described above is used as thedrive-pulley apparatus 6 for the engine-starting apparatus for theidling-stop vehicle shown in FIG. 55, is as described below. First, whenstarting the engine, electric power flows to the starter motor 4, whichrotates the sleeve 18 that is fastened to the end of the rotation-driveshaft 5 and the clutch inner ring 29 that is fastened to this sleeve 18in the counterclockwise direction of FIGS. 50 and 51. Therefore, therollers 33 move in the counterclockwise direction of FIGS. 50 and 51 inthe substantially cylindrical space between the outer peripheral surfaceof the clutch inner ring 29 and the inner peripheral surface of theclutch outer ring 30 toward the section where the width in the radialdirection becomes narrow. As a result, the rollers 33 become wedgedbetween the outer peripheral surface of the clutch inner ring 29 and theinner peripheral surface of the clutch outer ring 30, and the clutchroller 20 is in the locked state and transmits power from the clutchinner ring 29 to the clutch outer ring 30. In this state, the crankshaft2 of the engine 1 (see FIG. 55) is rotated and driven by way of thepulley element 17, endless belt 7 and follower pulley 3, and the engine1 starts.

After the engine 1 has started, electric power stops flowing to thestarter motor 4 and the rotation-drive shaft 5 stops. In this state, thepulley element 17 is rotated and driven by the crankshaft 2 of theengine 1 by way of the follower pulley 3 and endless belt 7, and theclutch outer ring 30 continues to rotate in the counterclockwisedirection of FIGS. 50 and 51. As a result, the roller clutch 20 is inthe overrun state and does not transmit the rotation of the pulleyelement 17 to the sleeve 18. Therefore, when the engine 1 is operating,the starter motor 4 does not become a load against the rotation of theengine 1.

When the roller clutch 20 is in the overrun state like this, the rollers33 are pressed by the column sections 36 of the clutch retainer 34 andthe springs 40, to rotate together with the clutch outer ring 30 that isfitted and fastened inside the pulley element 17. However, when the rpmof this clutch outer ring 30 is less than the rpm required to start theengine 1 (for example, in the case of a gasoline engine, speed aftermultiplying the transmission ratio of the belt transmission to 400 rpmto 500 rpm), the centrifugal force acting on the rollers 33 is not avalue that will compress the springs 40. Also, when starting the engine1, a force in the same direction as the elastic force of the springs 40is applied to the rollers 33 from the outer peripheral surface of theclutch inner ring 29. Therefore, when starting the engine, the rollers33 definitely move in the space between the outer peripheral surface ofthe clutch inner ring 29 and the inner peripheral surface of the clutchouter ring 30 toward the section where the width becomes narrow, and theroller clutch 20 becomes securely locked.

On the other hand, when the engine 1 starts and the rpm of the clutchouter ring 30 is greater than the rpm corresponding to idling of theengine 1 (for example, in the case of a gasoline engine, speed aftermultiplying the transmission ratio of the belt transmission to 700 rpmto 800 rpm), the rollers 33 press the springs 40 and move to the deepside of the concave sections 32 due to the centrifugal force. As aresult, not only is the connection of the roller clutch 20 broken (theoverrun state is set), but the rolling contact surfaces of the rollers33 of the roller clutch 20 separate from the outer peripheral surface ofthe clutch inner ring 29.

In other words, when the engine is operating, centrifugal force acts onthe rollers 33 and these rollers 33 are pressed against the bottomsurface of the concave sections 32. Since the bottom surfaces of theconcave sections 32 are inclined, the rollers 33 tend to move in thedirection that will press the springs 40 (compress the springs 40).Also, after the engine 1 starts and electric power stops flowing to thestarter motor 4, the clutch inner ring 29 stops, so the force moving therollers 33 in the counterclockwise direction of the FIGS. 50 and 51 isjust the elastic force of the springs 40.

In this state, the centrifugal force increases due to the rise inrotation force, and when the size of this component force becomesgreater than the elastic force of the springs 40, the rollers 33compress the springs 40 and moves toward the deep section of the concavesections 32. As a result, as described above, the rolling contactsurfaces of the rollers 33 separate from the outer peripheral surface ofthe clutch inner ring 29. In this state, regardless of the high rpm ofthe engine 1, it is possible to keep the friction heat that is generatedinside the roller clutch 20 to a minimum, and as described above, it ispossible to improve the durability of the roller clutch 20 and theadjacent ball bearings 19. Of course, it is also possible to preventdamage, such as uneven wear and seizure, to the roller clutch 20 itself.

However, when using the pulley apparatus with built-in roller clutch ofthe prior invention described above, after the engine starts, before therollers 33 press the springs 40 and move into the deep side of theconcave sections 32 due to the centrifugal force, there is rubbingbetween the rolling contact surfaces of the rollers 33 and the outerperipheral surface of the clutch inner ring 29. Therefore, in thisstate, providing a sufficient amount of grease at the points of slidingcontact between the rolling contact surfaces of the rollers 33 and theouter peripheral surface of the clutch inner ring 29 makes it possibleto prevent friction at these surfaces, and is very essential from theaspect of maintaining the durability of the pulley apparatus withbuilt-in roller clutch.

On the other hand, in the case of the clutch retainer 34 of the priorinvention, since the inner peripheral edge of the rim sections 35 andthe inner peripheral surface of the column sections 36 exist on onecylindrical surface, it is difficult to supply a sufficient amount ofgrease at the points of sliding contact. In other words, in the case ofthe clutch retainer 34, the column sections scrape away the grease atthe areas of contact on the outer peripheral surface of the clutch innerring 29 and the rolling contact surfaces of the rollers 33, so there ishardly any function of maintaining grease for supplying to this area.Therefore, prevention of wear at these surfaces becomes insufficient,and there is a possibility that durability of the pulley apparatus withbuilt-in roller clutch will not be sufficient.

The twenty-third to twenty-sixth example of the embodiments of theinvention shown in FIGS. 44 to 48 were invented with this problem takeninto consideration.

First, FIGS. 44 and 45 show a twenty-third example of the invention. Thefeature of this example is that by changing the construction of theclutch retainer 34 b a sufficient amount of grease is supplied to thepoints of contact (see FIGS. 49 to 51) between the outer peripheralsurface of the clutch inner ring 29 and the rolling contact surfaces ofthe rollers 33. The construction and function of the other parts, forexample the overall construction of the pulley apparatus with built-inroller clutch is substantially the same as in the previous inventionshown in FIGS. 49 to 51 and described above, so any drawings andexplanations of identical parts are omitted and this explanation centerson the features of this embodiment.

In the case of this example, the entire inner peripheral surface 74 ofthe column sections 36 b of the clutch retainer 34 b is more recessed inthe outward radial direction than the inner peripheral edge 75 of therim sections 35. Also, the inner diameter of the rim sections 35 isslightly greater than the outer diameter of the clutch inner ring 29.Therefore, when the clutch retainer 34 b is assembled into the pulleyapparatus with built-in roller clutch, the inner peripheral edges 75come close to and face both ends of the outer peripheral surface of theclutch inner ring 29. In other words, a labyrinth space 76 existsbetween the inner peripheral edges 75 and both ends of the outerperipheral surface of the clutch inner ring 29 that is too small forgrease to flow freely through. On the other hand, there is a plentylarge space 77 between the inner peripheral surface 74 of the columnsections 36 b and the middle section of the outer peripheral surface ofthe clutch inner ring 29.

When the rotation-transmission apparatus with built-in roller clutch forstarting an engine in which the clutch retainer 34 b described above isassembled is operating, grease enters the space 77. That is, the greasethat is filled inside the roller clutch 20 (see FIGS. 49 to 51) andadheres to the rolling contact surfaces of the rollers 33, or the greasethat is pushed in the circumferential direction of the roller clutch 20by the rollers 33, enters the space 77. This space 77 has sufficientvolume and is partitioned on the outside in the radial direction by theinner peripheral surfaces 74 of the column sections 36 b, and on bothsides in the axial direction by the rim sections 35. Therefore, it isdifficult for the grease that enters into this space 77 to flow out inthe radial direction even when a centrifugal force is applied when theclutch retainer 34 b rotates together with the pulley element 17 andclutch outer ring 30. Also, due to the existence of the labyrinth space76, 76 it is difficult for the grease to leak to the outside in theaxial direction.

Therefore, the grease that is taken into the space 77 is efficientlysupplied to the points of contact between the outer peripheral surfaceof the clutch inner ring 29 and the rolling contact surfaces of therollers 33, and prevents wear of these surfaces. As a result, even whenthere is rubbing between both of these surfaces, wear of these surfacesis suppressed, and it is possible to improve the durability of therotation-transmission apparatus with built-in roller clutch for startingan engine.

Next, FIG. 46 shows a twenty-fourth example of the embodiment of theinvention. In this example, the inner peripheral surface 74 a of thecolumn sections 36 c and the inner peripheral edge 75 of the rimsections 35 are located on a single cylindrical surface. However, inthis example, a concave holes 78 are formed in the center sections inthe circumferential direction of the inner peripheral surface 74 a ofthe column sections 36 c, and these concave holes 78 are formed tofunction as grease pockets. Also, the concave holes 78 have a crescentcross-sectional shape such that the depth becomes shallower toward bothends in the circumferential direction, so the grease that is taken intothe concave hole 78 is efficiently supplied to the outer peripheralsurface of the clutch inner ring 29 when there is relative rotationbetween the clutch retainer 34 c and the clutch inner ring 29.

The other construction and function is the same as in the twenty-thirdexample shown in FIGS. 44 and 45 described above.

Next, FIG. 47 shows a twenty-fifth example of the embodiment of theinvention. In this example, the inner peripheral surface 74 a of thecolumn sections 36 d and the inner peripheral edges 75 of the rimsections 35 are location on one cylindrical surface. However, in thisexample, half in the circumferential direction of the inner peripheralsurface 74 a of the column sections 36 d is a stepped concave section 79that is recessed outward in the radial direction, and this steppedconcave section 79 functions as a grease pocket. Also, these steppedconcave sections 79 directly face the rollers 33 that are held in thepockets 37 (see FIGS. 49 to 51), such that the grease taken into thesestepped concave sections 79 is efficiently supplied to the outerperipheral surface of the clutch inner ring 29 when there is relativerotation of the clutch retainer 34 d and the clutch inner ring 29 (seeFIGS. 49 to 51).

The other construction and functions are the substantially same as inthe twenty-third and twenty-fourth examples shown in FIGS. 44 to 46 anddescribed above.

Next, FIG. 48 shows a twenty-sixth example of the embodiment of theinvention. In this example, half in the circumferential direction of theinner peripheral surface 74 a of the column sections 36 e is an inclinedconcave section 80 that is recessed outward in the radial directiontoward the edge in the circumferential direction, to function as agrease pocket. In this example as well, these inclined concave sections80 directly face the rollers 33 that are held in the pockets 37 (seeFIGS. 49 to 51), such that the grease taken into these inclined concavesections 80 is efficiently supplied to the outer peripheral surface ofthe clutch inner ring 29 when there is relative rotation of the clutchretainer 34 e and the clutch inner ring 29 (see FIGS. 49 to 51). Theother construction and functions are substantially the same as in thetwenty-third and twenty-fifth examples shown in FIGS. 44 to 47 anddescribed above.

The twenty-third to twenty-sixth examples shown in FIGS. 44 to 48 anddescribed above were applied for the case in which therotation-transmission apparatus with built-in roller clutch wasassembled in the engine-starting apparatus for an idling-stop vehicle.However, the rotation-transmission apparatus with built-in roller clutchis not limited to this kind of application, and can also be usedassembled in various rotation-transmission mechanisms when the engine inan idling-stop vehicle is stopped, such as in a mechanism that drives anauxiliary device such as a compressor. A summary of the construction ofthe pulley apparatus with built-in roller clutch of the twenty-third totwenty-sixth examples described above is given below.

In other words, similar to the prior known pulley apparatus withbuilt-in roller, this pulley apparatus with built-in roller clutchcomprises: a circular-shaped pulley that has an endless belt that runsaround its outer peripheral surface and rotates only in a specifieddirection during use; a rotating shaft that is inserted though thecenter of this pulley and rotates in only a specified direction duringuse; and a roller clutch that is located in the circular-ring shapedspace between the inner peripheral surface of the pulley and the outerperipheral surface of the rotating shaft. Also, this roller clutchbecomes engaged when the rotating shaft rotates in the specifieddirection to transmit power from this rotating shaft to the pulley,however, when the pulley rotates faster than this rotating shaft, theroller clutch becomes disengaged and it does not transmit power fromthis pulley to the rotating shaft.

Particularly, in the pulley apparatus with built-in roller clutch of thetwenty-third to twenty-sixth examples described above, the cam surfacethat allows the plurality of rollers of the roller clutch to move in theradial direction of the pulley is located on the inner peripheralsurface of the pulley or on the inner peripheral surface of the clutchouter ring that is fitted and fastened inside this pulley.

Also, the outer peripheral surface of the rotating shaft or the outerperipheral surface of the clutch inner ring that is fastened around thisrotating shaft is a cylindrical surface, and a clutch retainer thatholds the rollers such that they can freely move in the circumferentialdirection of the circular-ring shaped space and also holds the springsfor pressing these rollers in the same circumferential direction in thiscircular-ring shaped space rotates with the pulley with respect to therotating shaft.

Furthermore, in the case of the pulley apparatus with built-in rollerclutch of the twenty-third to twenty-sixth examples described above, thegrease pockets are formed on the inner peripheral surface of theretainer for holding grease.

In the case of the pulley apparatus with built-in roller clutch of thetwenty-third to the twenty sixth examples described above grease issupplied from the grease pockets formed in the inner peripheral surfaceof the retainer to the points of contact between the rolling contactsurfaces of the rollers and the outer peripheral surface of the rotatingshaft or outer peripheral surface of the clutch inner ring that isfastened around the outside of this rotating shaft. Therefore, even whenthere is rubbing between these surfaces, it is possible to suppressfriction between these surfaces, and thus it is possible to improve thedurability of the pulley apparatus with built-in roller clutch.Therefore, even when there is high-speed relative rotation of the clutchouter ring and clutch inner ring, it is possible to maintain thedurability of the roller clutch. As a result, it is possible to improvethe performance of various mechanical apparatuses, such as improving thereliability and durability of the engine-starting apparatus for anidling-stop vehicle.

In each of the examples described above, the case is explained in whichthe rotating member described in the claims is a pulley element 17 (seeFIG. 1, etc.) around whose outer peripheral surface an endless beltruns. However, the rotation-transmission apparatus with built-in rollerclutch for starting an engine of this invention is not limited to thisconstruction, for example, construction in which an element having agear unit formed around its outer peripheral surface can be used as therotating member. In the case of using this kind of element, a differentgear unit that rotates with the engine crankshaft meshes with the gearunit that is formed on this element.

Also, the features of the invention disclosed in the claims, can beapplied separately, or part or all of the features of the inventiondisclosed in the claims can be combined. Moreover, it is possible tosuitably exclude part of the totally combined features of the invention.

Industrial Applicability

The rotation-transmission apparatus with built-in roller clutch forstarting an engine of this invention is constructed and functions asdescribed above, so it is possible to improve reliability and durabilityof the engine-starting apparatus for an idling-stop vehicle.

1. A rotation-transmission unit with built-in roller clutch for startingan engine for transmitting power in a specified direction between arotating member which rotates together with a crankshaft of an engineduring use and the rotating shaft of the motor for starting the enginewhich is inserted into the center of the rotating member to rotate inthe specified direction during use, the rotation-transmission unitcomprising a pair of support bearings provided in a circular spacebetween the inner peripheral surface of the rotating member and theouter peripheral surface of the rotating shaft and spaced apart fromeach other in the axial direction, a roller clutch provided between thesupport bearings in the circular space, the roller clutch becomingengaged when the rotating shaft rotates in the specified direction totransmit power from the rotating shaft to the rotating member, andbecoming idling when the rotating member rotates faster than therotating shaft in the specified direction so as not to transmit powerfrom the rotating member to the rotating shaft, and seal rings beingprovided on the opposite ends of the support bearings, such that theseal ring on the outer side opposite to the roller clutch is of thecontact type while the seal ring on the inner side near the rollerclutch is of the non-contact type.